diff --git a/paramiko/client.py b/paramiko/client.py
index 4adcfe7..be89609 100644
--- a/paramiko/client.py
+++ b/paramiko/client.py
@@ -190,7 +190,7 @@ class SSHClient (object):
         # update local host keys from file (in case other SSH clients
         # have written to the known_hosts file meanwhile.
         if self._host_keys_filename is not None:
-            self.load_host_keys(self._known_keys_filename)
+            self.load_host_keys(self._host_keys_filename)
 
         f = open(filename, 'w')
         for hostname, keys in self._host_keys.iteritems():