BACKGROUND: Penile entrapment and subsequent strangulation is a serious injury that requires a prompt treatment to avoid gangrene. OBJECTIVE: We report our experience dealing with a case of penile gangrene following strangulation by a metallic nut in a middle aged Nigerian. METHODS: We summarise the case history, physical findings, investigations and operative treatment of a middle aged man who slipped a round metallic nut over his penis, entrapping it for five days causing strangulation and subsequent gangrene. The literature on penile entrapment, strangulation and gangrene is also reviewed. RESULTS: The patient presented with acute urinary retention and had complete gangrene of the penis. Suprapubic cystostomy was done and he had total penile amputation and perineal urethrostomy CONCLUSION: Entrapment of the penis leading to strangulation is a rare condition that needs urgent relief, otherwise penile gangrene sets in, the treatment of which has very serious consequences.