diff --git a/lib/mongo/connection.rb b/lib/mongo/connection.rb
index ee48648..fbc2451 100644
--- a/lib/mongo/connection.rb
+++ b/lib/mongo/connection.rb
@@ -629,7 +629,9 @@ module Mongo
       rescue OperationFailure, SocketError, SystemCallError, IOError
         close
       ensure
-        socket.close if socket
+        if socket
+          socket.close unless socket.closed?
+        end
       end
 
       config