A traumatic rupture of the bladder in a healthy child is extremely rare and is usually not considered during evaluation of abdominal pain or sepsis. However, a delay in the diagnosis of bladder perforation can result in morbid and sometimes catastrophic outcomes. We report a delayed diagnosis of spontaneous rupture of a congenital bladder diverticulum in a previously healthy child. This case demonstrates that spontaneous bladder rupture may be a rare cause of abdominal complaints and sepsis when the etiology at first seems unclear.