diff --git a/AUTHORS b/AUTHORS
index 860a7890..2d1a073a 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -122,3 +122,4 @@ that much better:
  * Sergey Nikitin
  * psychogenic
  * Stefan Wójcik
+ * dimonb
diff --git a/docs/changelog.rst b/docs/changelog.rst
index aa37af9b..737f997c 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -4,6 +4,7 @@ Changelog
 
 Changes in 0.7.X
 =================
+- Fixed reloading on sharded documents (hmarr/mongoengine#569)
 - Added NotUniqueError for duplicate keys (MongoEngine/mongoengine#62)
 - Added custom collection / sequence naming for SequenceFields (MongoEngine/mongoengine#92)
 - Fixed UnboundLocalError in composite index with pk field (MongoEngine/mongoengine#88)
diff --git a/mongoengine/base.py b/mongoengine/base.py
index 05a08e59..82f79d3b 100644
--- a/mongoengine/base.py
+++ b/mongoengine/base.py
@@ -949,8 +949,10 @@ class BaseDocument(object):
                 self._data[name] = value
                 if hasattr(self, '_changed_fields'):
                     self._mark_as_changed(name)
+
         if (self._is_document and not self._created and
-            name in self._meta.get('shard_key', tuple())):
+            name in self._meta.get('shard_key', tuple()) and
+            self._data.get(name) != value):
             OperationError = _import_class('OperationError')
             msg = "Shard Keys are immutable. Tried to update %s" % name
             raise OperationError(msg)
diff --git a/mongoengine/document.py b/mongoengine/document.py
index 1691df93..9d528cbc 100644
--- a/mongoengine/document.py
+++ b/mongoengine/document.py
@@ -295,6 +295,16 @@ class Document(BaseDocument):
                 ref.save(**kwargs)
                 ref._changed_fields = []
 
+    @property
+    def _object_key(self):
+        """Dict to identify object in collection
+        """
+        select_dict = {'pk': self.pk}
+        shard_key = self.__class__._meta.get('shard_key', tuple())
+        for k in shard_key:
+            select_dict[k] = getattr(self, k)
+        return select_dict
+
     def update(self, **kwargs):
         """Performs an update on the :class:`~mongoengine.Document`
         A convenience wrapper to :meth:`~mongoengine.QuerySet.update`.
@@ -306,11 +316,7 @@ class Document(BaseDocument):
             raise OperationError('attempt to update a document not yet saved')
 
         # Need to add shard key to query, or you get an error
-        select_dict = {'pk': self.pk}
-        shard_key = self.__class__._meta.get('shard_key', tuple())
-        for k in shard_key:
-            select_dict[k] = getattr(self, k)
-        return self.__class__.objects(**select_dict).update_one(**kwargs)
+        return self.__class__.objects(**self._object_key).update_one(**kwargs)
 
     def delete(self, safe=False):
         """Delete the :class:`~mongoengine.Document` from the database. This
@@ -321,7 +327,7 @@ class Document(BaseDocument):
         signals.pre_delete.send(self.__class__, document=self)
 
         try:
-            self.__class__.objects(pk=self.pk).delete(safe=safe)
+            self.__class__.objects(**self._object_key).delete(safe=safe)
         except pymongo.errors.OperationFailure, err:
             message = u'Could not delete document (%s)' % err.message
             raise OperationError(message)
diff --git a/tests/test_document.py b/tests/test_document.py
index 350defd7..821637ea 100644
--- a/tests/test_document.py
+++ b/tests/test_document.py
@@ -1258,6 +1258,17 @@ class DocumentTest(unittest.TestCase):
         self.assertEqual(person.name, "Mr Test User")
         self.assertEqual(person.age, 21)
 
+    def test_reload_sharded(self):
+        class Animal(Document):
+            superphylum = StringField()
+            meta = {'shard_key': ('superphylum',)}
+
+        Animal.drop_collection()
+        doc = Animal(superphylum = 'Deuterostomia')
+        doc.save()
+        doc.reload()
+        Animal.drop_collection()
+
     def test_reload_referencing(self):
         """Ensures reloading updates weakrefs correctly
         """