diff --git a/README.rst b/README.rst
index 815665d..6cea178 100644
--- a/README.rst
+++ b/README.rst
@@ -182,8 +182,59 @@ on the same route, you must use *apps_to_expose* parameters
 
     oas.setup(app, apps_to_expose=[app, sub_app_1])
 
+
+Add annotation to define response content
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The module aiohttp_pydantic.oas.typing provides class to annotate a
+response content.
+
+For example *r200[List[Pet]]* means the server responses with
+the status code 200 and the response content is a List of Pet where Pet will be
+defined using a pydantic.BaseModel
+
+
+.. code-block:: python3
+
+    from aiohttp_pydantic import PydanticView
+    from aiohttp_pydantic.oas.typing import r200, r201, r204, r404
+
+
+    class Pet(BaseModel):
+        id: int
+        name: str
+
+
+    class Error(BaseModel):
+        error: str
+
+
+    class PetCollectionView(PydanticView):
+        async def get(self) -> r200[List[Pet]]:
+            pets = self.request.app["model"].list_pets()
+            return web.json_response([pet.dict() for pet in pets])
+
+        async def post(self, pet: Pet) -> r201[Pet]:
+            self.request.app["model"].add_pet(pet)
+            return web.json_response(pet.dict())
+
+
+    class PetItemView(PydanticView):
+        async def get(self, id: int, /) -> Union[r200[Pet], r404[Error]]:
+            pet = self.request.app["model"].find_pet(id)
+            return web.json_response(pet.dict())
+
+        async def put(self, id: int, /, pet: Pet) -> r200[Pet]:
+            self.request.app["model"].update_pet(id, pet)
+            return web.json_response(pet.dict())
+
+        async def delete(self, id: int, /) -> r204:
+            self.request.app["model"].remove_pet(id)
+            return web.Response(status=204)
+
+
 Demo
-====
+----
 
 Have a look at `demo`_ for a complete example
 
@@ -197,5 +248,4 @@ Have a look at `demo`_ for a complete example
 Go to http://127.0.0.1:8080/oas
 
 
-
 .. _demo: https://github.com/Maillol/aiohttp-pydantic/tree/main/demo
diff --git a/aiohttp_pydantic/injectors.py b/aiohttp_pydantic/injectors.py
index f96fccc..8594459 100644
--- a/aiohttp_pydantic/injectors.py
+++ b/aiohttp_pydantic/injectors.py
@@ -1,11 +1,9 @@
+import abc
+from inspect import signature
 from typing import Callable, Tuple
 
 from aiohttp.web_request import BaseRequest
 from pydantic import BaseModel
-from inspect import signature
-
-
-import abc
 
 
 class AbstractInjector(metaclass=abc.ABCMeta):
diff --git a/aiohttp_pydantic/oas/__init__.py b/aiohttp_pydantic/oas/__init__.py
index 939ec13..ef45dcf 100644
--- a/aiohttp_pydantic/oas/__init__.py
+++ b/aiohttp_pydantic/oas/__init__.py
@@ -1,11 +1,12 @@
-from typing import Iterable
 from importlib import resources
+from typing import Iterable
 
 import jinja2
 from aiohttp import web
-from .view import get_oas, oas_ui
 from swagger_ui_bundle import swagger_ui_path
 
+from .view import get_oas, oas_ui
+
 
 def setup(
     app: web.Application,
diff --git a/aiohttp_pydantic/oas/struct.py b/aiohttp_pydantic/oas/struct.py
index 4d62a19..6751c3f 100644
--- a/aiohttp_pydantic/oas/struct.py
+++ b/aiohttp_pydantic/oas/struct.py
@@ -1,3 +1,6 @@
+from typing import Union
+
+
 class Info:
     def __init__(self, spec: dict):
         self._spec = spec.setdefault("info", {})
@@ -115,6 +118,39 @@ class Parameters:
         return Parameter(spec)
 
 
+class Response:
+    def __init__(self, spec: dict):
+        self._spec = spec
+
+    @property
+    def description(self) -> str:
+        return self._spec["description"]
+
+    @description.setter
+    def description(self, description: str):
+        self._spec["description"] = description
+
+    @property
+    def content(self):
+        return self._spec["content"]
+
+    @content.setter
+    def content(self, content: dict):
+        self._spec["content"] = content
+
+
+class Responses:
+    def __init__(self, spec: dict):
+        self._spec = spec.setdefault("responses", {})
+
+    def __getitem__(self, status_code: Union[int, str]) -> Response:
+        if not (100 <= int(status_code) < 600):
+            raise ValueError("status_code must be between 100 and 599")
+
+        spec = self._spec.setdefault(str(status_code), {})
+        return Response(spec)
+
+
 class OperationObject:
     def __init__(self, spec: dict):
         self._spec = spec
@@ -143,6 +179,10 @@ class OperationObject:
     def parameters(self) -> Parameters:
         return Parameters(self._spec)
 
+    @property
+    def responses(self) -> Responses:
+        return Responses(self._spec)
+
 
 class PathItem:
     def __init__(self, spec: dict):
diff --git a/aiohttp_pydantic/oas/typing.py b/aiohttp_pydantic/oas/typing.py
new file mode 100644
index 0000000..5be1cd7
--- /dev/null
+++ b/aiohttp_pydantic/oas/typing.py
@@ -0,0 +1,47 @@
+"""
+This module provides type to annotate the content of web.Response returned by
+the HTTP handlers.
+
+The type are: r100, r101, ..., r599
+
+Example:
+
+    class PetCollectionView(PydanticView):
+        async def get(self) -> Union[r200[List[Pet]], r404]:
+            ...
+"""
+
+from functools import lru_cache
+from types import new_class
+from typing import Protocol, TypeVar
+
+RespContents = TypeVar("RespContents", covariant=True)
+
+_status_code = frozenset(f"r{code}" for code in range(100, 600))
+
+
+@lru_cache(maxsize=len(_status_code))
+def _make_status_code_type(status_code):
+    if status_code in _status_code:
+        return new_class(status_code, (Protocol[RespContents],))
+
+
+def is_status_code_type(obj):
+    """
+    Return True if obj is a status code type such as _200 or _404.
+    """
+    name = getattr(obj, "__name__", None)
+    if name not in _status_code:
+        return False
+
+    return obj is _make_status_code_type(name)
+
+
+def __getattr__(name):
+    if (status_code_type := _make_status_code_type(name)) is None:
+        raise AttributeError(f"module {__name__!r} has no attribute {name!r}")
+    return status_code_type
+
+
+__all__ = list(_status_code)
+__all__.append("is_status_code_type")
diff --git a/aiohttp_pydantic/oas/view.py b/aiohttp_pydantic/oas/view.py
index 52e0408..7daa830 100644
--- a/aiohttp_pydantic/oas/view.py
+++ b/aiohttp_pydantic/oas/view.py
@@ -1,44 +1,109 @@
-from aiohttp.web import json_response, Response
+import typing
+from typing import Type
+
+from aiohttp.web import Response, json_response
+from pydantic import BaseModel
 
 from aiohttp_pydantic.oas.struct import OpenApiSpec3, OperationObject, PathItem
-from typing import Type
 
 from ..injectors import _parse_func_signature
 from ..view import PydanticView, is_pydantic_view
-
+from .typing import is_status_code_type
 
 JSON_SCHEMA_TYPES = {float: "number", str: "string", int: "integer"}
 
 
-def _add_http_method_to_oas(oas_path: PathItem, method: str, view: Type[PydanticView]):
-    method = method.lower()
-    mtd: OperationObject = getattr(oas_path, method)
-    handler = getattr(view, method)
+def _is_pydantic_base_model(obj):
+    """
+    Return true is obj is a pydantic.BaseModel subclass.
+    """
+    try:
+        return issubclass(obj, BaseModel)
+    except TypeError:
+        return False
+
+
+class _OASResponseBuilder:
+    """
+    Parse the type annotated as returned by a function and
+    generate the OAS operation response.
+    """
+
+    def __init__(self, oas_operation):
+        self._oas_operation = oas_operation
+
+    @staticmethod
+    def _handle_pydantic_base_model(obj):
+        if _is_pydantic_base_model(obj):
+            return obj.schema()
+        return {}
+
+    def _handle_list(self, obj):
+        if typing.get_origin(obj) is list:
+            return {
+                "type": "array",
+                "items": self._handle_pydantic_base_model(typing.get_args(obj)[0]),
+            }
+        return self._handle_pydantic_base_model(obj)
+
+    def _handle_status_code_type(self, obj):
+        if is_status_code_type(typing.get_origin(obj)):
+            status_code = typing.get_origin(obj).__name__[1:]
+            self._oas_operation.responses[status_code].content = {
+                "application/json": {
+                    "schema": self._handle_list(typing.get_args(obj)[0])
+                }
+            }
+
+        elif is_status_code_type(obj):
+            status_code = obj.__name__[1:]
+            self._oas_operation.responses[status_code].content = {}
+
+    def _handle_union(self, obj):
+        if typing.get_origin(obj) is typing.Union:
+            for arg in typing.get_args(obj):
+                self._handle_status_code_type(arg)
+        self._handle_status_code_type(obj)
+
+    def build(self, obj):
+        self._handle_union(obj)
+
+
+def _add_http_method_to_oas(
+    oas_path: PathItem, http_method: str, view: Type[PydanticView]
+):
+    http_method = http_method.lower()
+    oas_operation: OperationObject = getattr(oas_path, http_method)
+    handler = getattr(view, http_method)
     path_args, body_args, qs_args, header_args = _parse_func_signature(handler)
 
     if body_args:
-        mtd.request_body.content = {
+        oas_operation.request_body.content = {
             "application/json": {"schema": next(iter(body_args.values())).schema()}
         }
 
     i = 0
     for i, (name, type_) in enumerate(path_args.items()):
-        mtd.parameters[i].required = True
-        mtd.parameters[i].in_ = "path"
-        mtd.parameters[i].name = name
-        mtd.parameters[i].schema = {"type": JSON_SCHEMA_TYPES[type_]}
+        oas_operation.parameters[i].required = True
+        oas_operation.parameters[i].in_ = "path"
+        oas_operation.parameters[i].name = name
+        oas_operation.parameters[i].schema = {"type": JSON_SCHEMA_TYPES[type_]}
 
     for i, (name, type_) in enumerate(qs_args.items(), i + 1):
-        mtd.parameters[i].required = False
-        mtd.parameters[i].in_ = "query"
-        mtd.parameters[i].name = name
-        mtd.parameters[i].schema = {"type": JSON_SCHEMA_TYPES[type_]}
+        oas_operation.parameters[i].required = False
+        oas_operation.parameters[i].in_ = "query"
+        oas_operation.parameters[i].name = name
+        oas_operation.parameters[i].schema = {"type": JSON_SCHEMA_TYPES[type_]}
 
     for i, (name, type_) in enumerate(header_args.items(), i + 1):
-        mtd.parameters[i].required = False
-        mtd.parameters[i].in_ = "header"
-        mtd.parameters[i].name = name
-        mtd.parameters[i].schema = {"type": JSON_SCHEMA_TYPES[type_]}
+        oas_operation.parameters[i].required = False
+        oas_operation.parameters[i].in_ = "header"
+        oas_operation.parameters[i].name = name
+        oas_operation.parameters[i].schema = {"type": JSON_SCHEMA_TYPES[type_]}
+
+    return_type = handler.__annotations__.get("return")
+    if return_type is not None:
+        _OASResponseBuilder(oas_operation).build(return_type)
 
 
 async def get_oas(request):
diff --git a/aiohttp_pydantic/view.py b/aiohttp_pydantic/view.py
index e5b8587..a899542 100644
--- a/aiohttp_pydantic/view.py
+++ b/aiohttp_pydantic/view.py
@@ -1,22 +1,16 @@
+from functools import update_wrapper
 from inspect import iscoroutinefunction
+from typing import Any, Callable, Generator, Iterable
+
 from aiohttp.abc import AbstractView
 from aiohttp.hdrs import METH_ALL
+from aiohttp.web import json_response
 from aiohttp.web_exceptions import HTTPMethodNotAllowed
 from aiohttp.web_response import StreamResponse
 from pydantic import ValidationError
-from typing import Generator, Any, Callable, Type, Iterable
-from aiohttp.web import json_response
-from functools import update_wrapper
 
-
-from .injectors import (
-    MatchInfoGetter,
-    HeadersGetter,
-    QueryGetter,
-    BodyGetter,
-    AbstractInjector,
-    _parse_func_signature,
-)
+from .injectors import (AbstractInjector, BodyGetter, HeadersGetter,
+                        MatchInfoGetter, QueryGetter, _parse_func_signature)
 
 
 class PydanticView(AbstractView):
diff --git a/demo/__main__.py b/demo/__main__.py
index 58025fb..5ca79a0 100644
--- a/demo/__main__.py
+++ b/demo/__main__.py
@@ -1,10 +1,10 @@
 from aiohttp import web
-
-from aiohttp_pydantic import oas
 from aiohttp.web import middleware
 
-from .view import PetItemView, PetCollectionView
+from aiohttp_pydantic import oas
+
 from .model import Model
+from .view import PetCollectionView, PetItemView
 
 
 @middleware
diff --git a/demo/model.py b/demo/model.py
index 3e1d4c7..a6ef842 100644
--- a/demo/model.py
+++ b/demo/model.py
@@ -6,6 +6,10 @@ class Pet(BaseModel):
     name: str
 
 
+class Error(BaseModel):
+    error: str
+
+
 class Model:
     """
     To keep simple this demo, we use a simple dict as database to
diff --git a/demo/view.py b/demo/view.py
index fe12ffc..b897f00 100644
--- a/demo/view.py
+++ b/demo/view.py
@@ -1,28 +1,32 @@
-from aiohttp_pydantic import PydanticView
+from typing import List, Union
+
 from aiohttp import web
 
-from .model import Pet
+from aiohttp_pydantic import PydanticView
+from aiohttp_pydantic.oas.typing import r200, r201, r204, r404
+
+from .model import Error, Pet
 
 
 class PetCollectionView(PydanticView):
-    async def get(self):
+    async def get(self) -> r200[List[Pet]]:
         pets = self.request.app["model"].list_pets()
         return web.json_response([pet.dict() for pet in pets])
 
-    async def post(self, pet: Pet):
+    async def post(self, pet: Pet) -> r201[Pet]:
         self.request.app["model"].add_pet(pet)
         return web.json_response(pet.dict())
 
 
 class PetItemView(PydanticView):
-    async def get(self, id: int, /):
+    async def get(self, id: int, /) -> Union[r200[Pet], r404[Error]]:
         pet = self.request.app["model"].find_pet(id)
         return web.json_response(pet.dict())
 
-    async def put(self, id: int, /, pet: Pet):
+    async def put(self, id: int, /, pet: Pet) -> r200[Pet]:
         self.request.app["model"].update_pet(id, pet)
         return web.json_response(pet.dict())
 
-    async def delete(self, id: int, /):
+    async def delete(self, id: int, /) -> r204:
         self.request.app["model"].remove_pet(id)
-        return web.json_response(id)
+        return web.Response(status=204)
diff --git a/tests/test_oas/test_view.py b/tests/test_oas/test_view.py
index 78f39ec..17332d0 100644
--- a/tests/test_oas/test_view.py
+++ b/tests/test_oas/test_view.py
@@ -1,8 +1,11 @@
-from pydantic.main import BaseModel
-from aiohttp_pydantic import PydanticView, oas
-from aiohttp import web
+from typing import List, Union
 
 import pytest
+from aiohttp import web
+from pydantic.main import BaseModel
+
+from aiohttp_pydantic import PydanticView, oas
+from aiohttp_pydantic.oas.typing import r200, r201, r204, r404
 
 
 class Pet(BaseModel):
@@ -11,21 +14,21 @@ class Pet(BaseModel):
 
 
 class PetCollectionView(PydanticView):
-    async def get(self):
+    async def get(self) -> r200[List[Pet]]:
         return web.json_response()
 
-    async def post(self, pet: Pet):
+    async def post(self, pet: Pet) -> r201[Pet]:
         return web.json_response()
 
 
 class PetItemView(PydanticView):
-    async def get(self, id: int, /):
+    async def get(self, id: int, /) -> Union[r200[Pet], r404]:
         return web.json_response()
 
     async def put(self, id: int, /, pet: Pet):
         return web.json_response()
 
-    async def delete(self, id: int, /):
+    async def delete(self, id: int, /) -> r204:
         return web.json_response()
 
 
@@ -48,7 +51,28 @@ async def test_generated_oas_should_have_pets_paths(generated_oas):
 
 
 async def test_pets_route_should_have_get_method(generated_oas):
-    assert generated_oas["paths"]["/pets"]["get"] == {}
+    assert generated_oas["paths"]["/pets"]["get"] == {
+        "responses": {
+            "200": {
+                "content": {
+                    "application/json": {
+                        "schema": {
+                            "type": "array",
+                            "items": {
+                                "title": "Pet",
+                                "type": "object",
+                                "properties": {
+                                    "id": {"title": "Id", "type": "integer"},
+                                    "name": {"title": "Name", "type": "string"},
+                                },
+                                "required": ["id", "name"],
+                            },
+                        }
+                    }
+                }
+            }
+        }
+    }
 
 
 async def test_pets_route_should_have_post_method(generated_oas):
@@ -57,17 +81,34 @@ async def test_pets_route_should_have_post_method(generated_oas):
             "content": {
                 "application/json": {
                     "schema": {
+                        "title": "Pet",
+                        "type": "object",
                         "properties": {
                             "id": {"title": "Id", "type": "integer"},
                             "name": {"title": "Name", "type": "string"},
                         },
                         "required": ["id", "name"],
-                        "title": "Pet",
-                        "type": "object",
                     }
                 }
             }
-        }
+        },
+        "responses": {
+            "201": {
+                "content": {
+                    "application/json": {
+                        "schema": {
+                            "title": "Pet",
+                            "type": "object",
+                            "properties": {
+                                "id": {"title": "Id", "type": "integer"},
+                                "name": {"title": "Name", "type": "string"},
+                            },
+                            "required": ["id", "name"],
+                        }
+                    }
+                }
+            }
+        },
     }
 
 
@@ -79,12 +120,13 @@ async def test_pets_id_route_should_have_delete_method(generated_oas):
     assert generated_oas["paths"]["/pets/{id}"]["delete"] == {
         "parameters": [
             {
+                "required": True,
                 "in": "path",
                 "name": "id",
-                "required": True,
                 "schema": {"type": "integer"},
             }
-        ]
+        ],
+        "responses": {"204": {"content": {}}},
     }
 
 
@@ -97,7 +139,25 @@ async def test_pets_id_route_should_have_get_method(generated_oas):
                 "required": True,
                 "schema": {"type": "integer"},
             }
-        ]
+        ],
+        "responses": {
+            "200": {
+                "content": {
+                    "application/json": {
+                        "schema": {
+                            "properties": {
+                                "id": {"title": "Id", "type": "integer"},
+                                "name": {"title": "Name", "type": "string"},
+                            },
+                            "required": ["id", "name"],
+                            "title": "Pet",
+                            "type": "object",
+                        }
+                    }
+                }
+            },
+            "404": {"content": {}},
+        },
     }
 
 
diff --git a/tests/test_parse_func_signature.py b/tests/test_parse_func_signature.py
index 3c91e9f..c2cc47b 100644
--- a/tests/test_parse_func_signature.py
+++ b/tests/test_parse_func_signature.py
@@ -1,7 +1,9 @@
-from aiohttp_pydantic.injectors import _parse_func_signature
-from pydantic import BaseModel
 from uuid import UUID
 
+from pydantic import BaseModel
+
+from aiohttp_pydantic.injectors import _parse_func_signature
+
 
 class User(BaseModel):
     firstname: str
diff --git a/tests/test_validation_body.py b/tests/test_validation_body.py
index 33951fb..18cb97f 100644
--- a/tests/test_validation_body.py
+++ b/tests/test_validation_body.py
@@ -1,6 +1,8 @@
-from pydantic import BaseModel
 from typing import Optional
+
 from aiohttp import web
+from pydantic import BaseModel
+
 from aiohttp_pydantic import PydanticView
 
 
diff --git a/tests/test_validation_header.py b/tests/test_validation_header.py
index 511f45c..83558e1 100644
--- a/tests/test_validation_header.py
+++ b/tests/test_validation_header.py
@@ -1,7 +1,9 @@
-from aiohttp import web
-from aiohttp_pydantic import PydanticView
-from datetime import datetime
 import json
+from datetime import datetime
+
+from aiohttp import web
+
+from aiohttp_pydantic import PydanticView
 
 
 class JSONEncoder(json.JSONEncoder):
diff --git a/tests/test_validation_path.py b/tests/test_validation_path.py
index fe7466f..0e74e65 100644
--- a/tests/test_validation_path.py
+++ b/tests/test_validation_path.py
@@ -1,4 +1,5 @@
 from aiohttp import web
+
 from aiohttp_pydantic import PydanticView
 
 
diff --git a/tests/test_validation_query_string.py b/tests/test_validation_query_string.py
index 3df2336..441cf6e 100644
--- a/tests/test_validation_query_string.py
+++ b/tests/test_validation_query_string.py
@@ -1,4 +1,5 @@
 from aiohttp import web
+
 from aiohttp_pydantic import PydanticView