Fournier gangrene is a serious infectious disease with high mortality and morbidity rates characterized by rapidly progressive skin necrosis. Immediate debridement of infected necrotic tissue and broad spectrum antibiotic therapy are the main principles of the treatment. Size of the debrided area, advanced age, colorectal predisposition and renal insufficiency are the factors affecting the mortality. In this case report, we present a rare case of Fournier gangrene caused by migration of foreign body from rectum to bladder.