A case of a 12 years old school girl is described. She presented nine days after the onset of acute periumbilical abdominal pain which was later accompanied three days prior to admission by purulent discharge from the umbilicus. Radiological investigation revealed a pelvic collection of pus with retroperitoneal extensions. Late presentation made the attempt to save the patient unsuccessful. A review of the literature reveals that extensive intraperitoneal and retroperitoneal extension of abscess resulting from anomaly of the urachus is extremely rare.