diff --git a/rest_framework/serializers.py b/rest_framework/serializers.py
index 397866a76..2e7e2cf5d 100644
--- a/rest_framework/serializers.py
+++ b/rest_framework/serializers.py
@@ -277,6 +277,9 @@ class BaseSerializer(Field):
         """
         obj = getattr(obj, self.source or field_name)
 
+        if is_simple_callable(obj):
+            obj = obj()
+
         # If the object has an "all" method, assume it's a relationship
         if is_simple_callable(getattr(obj, 'all', None)):
             return [self.to_native(item) for item in obj.all()]
diff --git a/rest_framework/tests/models.py b/rest_framework/tests/models.py
index 59d811502..3704cda7b 100644
--- a/rest_framework/tests/models.py
+++ b/rest_framework/tests/models.py
@@ -127,6 +127,9 @@ class ActionItem(RESTFrameworkModel):
 class BlogPost(RESTFrameworkModel):
     title = models.CharField(max_length=100)
 
+    def get_first_comment(self):
+        return self.blogpostcomment_set.all()[0]
+
 
 class BlogPostComment(RESTFrameworkModel):
     text = models.TextField()
diff --git a/rest_framework/tests/serializer.py b/rest_framework/tests/serializer.py
index 814c24993..d522ef972 100644
--- a/rest_framework/tests/serializer.py
+++ b/rest_framework/tests/serializer.py
@@ -479,7 +479,10 @@ class CallableDefaultValueTests(TestCase):
 
 
 class ManyRelatedTests(TestCase):
-    def setUp(self):
+    def test_reverse_relations(self):
+        post = BlogPost.objects.create(title="Test blog post")
+        post.blogpostcomment_set.create(text="I hate this blog post")
+        post.blogpostcomment_set.create(text="I love this blog post")
 
         class BlogPostCommentSerializer(serializers.Serializer):
             text = serializers.CharField()
@@ -488,14 +491,7 @@ class ManyRelatedTests(TestCase):
             title = serializers.CharField()
             comments = BlogPostCommentSerializer(source='blogpostcomment_set')
 
-        self.serializer_class = BlogPostSerializer
-
-    def test_reverse_relations(self):
-        post = BlogPost.objects.create(title="Test blog post")
-        post.blogpostcomment_set.create(text="I hate this blog post")
-        post.blogpostcomment_set.create(text="I love this blog post")
-
-        serializer = self.serializer_class(instance=post)
+        serializer = BlogPostSerializer(instance=post)
         expected = {
             'title': 'Test blog post',
             'comments': [
@@ -506,6 +502,25 @@ class ManyRelatedTests(TestCase):
 
         self.assertEqual(serializer.data, expected)
 
+    def test_callable_source(self):
+        post = BlogPost.objects.create(title="Test blog post")
+        post.blogpostcomment_set.create(text="I love this blog post")
+
+        class BlogPostCommentSerializer(serializers.Serializer):
+            text = serializers.CharField()
+
+        class BlogPostSerializer(serializers.Serializer):
+            title = serializers.CharField()
+            first_comment = BlogPostCommentSerializer(source='get_first_comment')
+
+        serializer = BlogPostSerializer(post)
+
+        expected = {
+            'title': 'Test blog post',
+            'first_comment': {'text': 'I love this blog post'}
+        }
+        self.assertEqual(serializer.data, expected)
+
 
 # Test for issue #324
 class BlankFieldTests(TestCase):