diff --git a/src/cryptojwt/key_bundle.py b/src/cryptojwt/key_bundle.py
index <HASH>..<HASH> 100755
--- a/src/cryptojwt/key_bundle.py
+++ b/src/cryptojwt/key_bundle.py
@@ -208,7 +208,8 @@ class KeyBundle(object):
                     except JWKException as err:
                         logger.warning('While loading keys: {}'.format(err))
                     else:
-                        self._keys.append(_key)
+                        if _key not in self._keys:
+                            self._keys.append(_key)
                         flag = 1
                         break
             if not flag:
Don't add keys that are already there.