We report two rare cases of isolated spontaneous intraperitoneal bladder rupture following normal vaginal delivery without concomitant uterine rupture. Two primigravidas, aged 32 years and 34 years, presented following vaginal delivery with abdominal distension and acute renal failure. The initial diagnosis in both cases was severe urosepsis. Definitive diagnosis was achieved after 48 hours. Comparison was made with two of the cases found in the literature and all four cases were reviewed. Laparotomy and bladder repair were performed in all patients with no adverse outcome reported. Two of them were diagnosed only during laparotomy. Key diagnostic clinical features were acute renal failure, new-onset ascites and bowel ileus with sepsis. This rare but life-threatening condition is often diagnosed late. Prompt laparotomy and bladder repair are necessary to prevent an adverse outcome.