diff --git a/mongoengine/queryset.py b/mongoengine/queryset.py
index d5938795..c5997cf6 100644
--- a/mongoengine/queryset.py
+++ b/mongoengine/queryset.py
@@ -37,12 +37,16 @@ class QuerySet(object):
         for key, value in query.items():
             parts = key.split('__')
             # Check for an operator and transform to mongo-style if there is
+            op = None
             if parts[-1] in operators:
                 op = parts.pop()
                 value = {'$' + op: value}
 
             key = '.'.join(parts)
-            mongo_query[key] = value
+            if op is None or key not in mongo_query:
+                mongo_query[key] = value
+            elif key in mongo_query and isinstance(mongo_query[key], dict):
+                mongo_query[key].update(value)
 
         return mongo_query
 
diff --git a/tests/document.py b/tests/document.py
index 3dc91f36..c20e9b33 100644
--- a/tests/document.py
+++ b/tests/document.py
@@ -246,6 +246,8 @@ class DocumentTest(unittest.TestCase):
             content = StringField()
             author = ReferenceField(self.Person)
 
+        BlogPost.drop_collection()
+
         author = self.Person(name='Test User')
         author.save()
 
diff --git a/tests/queryset.py b/tests/queryset.py
index 2c650b4c..344ee65d 100644
--- a/tests/queryset.py
+++ b/tests/queryset.py
@@ -31,6 +31,10 @@ class QuerySetTest(unittest.TestCase):
                          {'name': 'test', 'age': 30})
         self.assertEqual(QuerySet._transform_query(age__lt=30), 
                          {'age': {'$lt': 30}})
+        self.assertEqual(QuerySet._transform_query(age__gt=20, age__lt=50),
+                         {'age': {'$gt': 20, '$lt': 50}})
+        self.assertEqual(QuerySet._transform_query(age=20, age__gt=50),
+                         {'age': 20})
         self.assertEqual(QuerySet._transform_query(friend__age__gte=30), 
                          {'friend.age': {'$gte': 30}})
         self.assertEqual(QuerySet._transform_query(name__exists=True),