diff --git a/flask_jwt/__init__.py b/flask_jwt/__init__.py
index f864b78..dd5688b 100644
--- a/flask_jwt/__init__.py
+++ b/flask_jwt/__init__.py
@@ -50,7 +50,7 @@ def _default_jwt_payload_handler(identity):
     iat = datetime.utcnow()
     exp = iat + current_app.config.get('JWT_EXPIRATION_DELTA')
     nbf = iat + current_app.config.get('JWT_NOT_BEFORE_DELTA')
-    identity = getattr(identity, 'id') or identity['id']
+    identity = getattr(identity, 'id', None) or identity['id']
     return {'exp': exp, 'iat': iat, 'nbf': nbf, 'identity': identity}
 
 
diff --git a/tests/test_jwt.py b/tests/test_jwt.py
index 2157003..29ba038 100644
--- a/tests/test_jwt.py
+++ b/tests/test_jwt.py
@@ -291,3 +291,16 @@ def custom_auth_request_handler():
     with app.test_client() as c:
         resp, jdata = post_json(c, '/auth', {})
         assert jdata == {'hello': 'world'}
+
+
+def test_authentication_handler_with_dictionary_result(client, jwt, user):
+    @jwt.authentication_handler
+    def authenticate(username, password):
+        if username == user.username and password == user.password:
+            return dict(id=user.id, username=user.username, password=user.password)
+        return None
+
+    resp, jdata = post_json(
+        client, '/auth', {'username': user.username, 'password': user.password})
+    assert resp.status_code == 200
+    assert 'access_token' in jdata
diff --git a/tox.ini b/tox.ini
index e9fda0a..93423eb 100644
--- a/tox.ini
+++ b/tox.ini
@@ -7,4 +7,4 @@ deps =
     -r{toxinidir}/requirements-dev.txt
 
 commands =
-    py.test --clearcache {posargs} ./tests
+    py.test --cache-clear {posargs} ./tests