BACKGROUNDSpontaneous kidney rupture could develop in the course of posterior urethral valve (PUV), the most common cause of outflow urinary tract obstruction in male infants. However, urinary extravasation is a rare complication among this group of children. CASE PRESENTATIONOur case report presents diagnostic difficulties connected with spontaneous kidney rupture due to PUV in a 6 week-old infant. Due to not equivocal images, thundery course of disease and rapid deterioration in the infant's condition, the patient required an urgent laparatomy. CONCLUSIONThis case showed that the investigation of renal abnormalities during early neonatal period, is very important specifically in PUV that can lead to kidney rupture.