diff --git a/lib/mongo/session.rb b/lib/mongo/session.rb
index 27d84d580d..c5a55fd168 100644
--- a/lib/mongo/session.rb
+++ b/lib/mongo/session.rb
@@ -1200,7 +1200,7 @@ def check_if_ended!
     end
 
     def check_matching_client!(client)
-      if @client != client
+      if @client.cluster != client.cluster
         raise Mongo::Error::InvalidSession.new(MISMATCHED_CLUSTER_ERROR_MSG)
       end
     end