Thank you for the responses. Specifying the bound instance method as the callback works. (I remember it did not work for me many months ago, hence my post). Works now. Thanks, -Arun --- On Sat, 6/4/11, A Desai <ardesai@yahoo.com> wrote: From: A Desai <ardesai@yahoo.com> Subject: Class methods as callbacks/errbacks To: twisted-web@twistedmatrix.com Date: Saturday, June 4, 2011, 9:31 PM I use a wrapper functions as follows to specify the callback argument of addCallback() and addErrback(). def reqConnLostCallbk(result, arg_self): arg_self.lost_conn() def reqConnLostErrbk(failure, arg_self): arg_self.lost_conn() ... inside a class method d.addCallback(reqConnLostCallbk, self) d.addErrback(reqConnLostErrbk, self) def lost_conn(self): // cleanup pass Is there an alternative and/or cleaner solution to specify a class method as a callback or errback? -Arun