Postpartum gangrenous cystitis is a rare condition with only a few reported cases in the literature. We report a case of a 26-year-old lady who developed gangrenous cystitis and perforation 48 hours after a prolonged labour when she presented in urinary retention and sepsis. Computerised Tomography (CT) scans revealed ascites. With clinical signs of peritonitis, emergency diagnostic laparoscopy was performed, identifying the bladder perforation. The procedure was converted to laparotomy and necrotic bladder tissue was excised and bladder was repaired. We highlight the important learning points from the case and review the current literature on aetiology, diagnostic challenges and management of this rare complication.