Background Bladder rupture caused by trauma or pelvic fracture is very common, and can be easily diagnosed. However, Spontaneous rupture of the bladder is rare. Reported by Peters PC. (Peters, Urol Clin N Am 16:279–82, 1989): The incidence of spontaneous bladder rupture is 1: 126000. During childbirth, the occurrence rate of this disease is lower than that of the former. It is very difficult to make an early diagnosis of the spontaneous rupture of the bladder during childbirth, which eventually results in high maternal mortality. Due to peritoneal reabsorption, the patient may show high levels of serum creatinine and potassium, and this would easily be misdiagnosed as acute renal failure. However, these patients have normal renal function, hence the diagnosis of renal failure is incorrect. Case presentation A 23 year-old female patient had her first pregnancy and delivered a full-term healthy baby girl. After delivery, the patient developed fever, oliguria, massive ascites, high serum creatinine and high serum potassium. The patient was initially diagnosed with acute renal failure, however treatment for her condition was ineffective. After further examination, the patient was diagnosed with intraperitoneal bladder rupture. The patient was treated for bladder rupture, made a full recovery and was discharged. Conclusions Sudden onset of massive ascites and renal failure due to abnormal serum biochemical characteristics after delivery should be first diagnosed as spontaneous bladder rupture. However, bladder radiography may suggest a false negative result, hence cystoscopy should be performed to confirm the diagnosis. The ratio between ascites creatinine and serum creatinine would be helpful for early diagnosis and to determine the time of rupture. Conservative management or surgical repair should be used to treat bladder rupture.