diff --git a/google/oauth2/credentials.py b/google/oauth2/credentials.py
index 24b3a3e..8e2a7f8 100644
--- a/google/oauth2/credentials.py
+++ b/google/oauth2/credentials.py
@@ -38,6 +38,7 @@
 
 from google.auth import _helpers
 from google.auth import credentials
+from google.auth import exceptions
 from google.oauth2 import _client
 
 
@@ -120,6 +121,15 @@
 
     @_helpers.copy_docstring(credentials.Credentials)
     def refresh(self, request):
+        if (self._refresh_token is None or
+                self._token_uri is None or
+                self._client_id is None or
+                self._client_secret is None):
+            raise exceptions.RefreshError(
+                'The credentials do not contain the necessary fields need to '
+                'refresh the access token. You must specify refresh_token, '
+                'token_uri, client_id, and client_secret.')
+
         access_token, refresh_token, expiry, grant_response = (
             _client.refresh_grant(
                 request, self._token_uri, self._refresh_token, self._client_id,