diff --git a/github/GithubException.py b/github/GithubException.py
index 0186c690..c72fad89 100644
--- a/github/GithubException.py
+++ b/github/GithubException.py
@@ -123,3 +123,9 @@ class TwoFactorException(GithubException):
     """
     Exception raised when Github requires a onetime password for two-factor authentication
     """
+
+
+class IncompletableObject(GithubException):
+    """
+    Exception raised when we can not request an object from Github because the data returned did not include a URL
+    """
diff --git a/github/GithubObject.py b/github/GithubObject.py
index f6a817aa..41581a56 100644
--- a/github/GithubObject.py
+++ b/github/GithubObject.py
@@ -266,6 +266,8 @@ class CompletableGithubObject(GithubObject):
             self.__complete()
 
     def __complete(self):
+        if self._url.value is None:
+            raise GithubException.IncompletableObject(400, "Returned object contains no URL")
         headers, data = self._requester.requestJsonAndCheck(
             "GET",
             self._url.value
diff --git a/tests/Exceptions.py b/tests/Exceptions.py
index 0f137765..9ee5dae4 100644
--- a/tests/Exceptions.py
+++ b/tests/Exceptions.py
@@ -33,6 +33,7 @@
 
 from __future__ import absolute_import
 import github
+from github.GithubException import IncompletableObject
 import pickle
 
 from . import Framework
@@ -122,3 +123,8 @@ class SpecificExceptions(Framework.TestCase):
                 res.get_page(0)
 
         self.assertRaises(github.RateLimitExceededException, exceed)
+
+    def testIncompletableObject(self):
+        github.UserKey.UserKey.setCheckAfterInitFlag(False)
+        obj = github.UserKey.UserKey(None, {}, {}, False)
+        self.assertRaises(IncompletableObject, obj._completeIfNeeded)