The rupture of the urinary bladder may cause acute abdomen. However, this has not been emphasized in the classical surgical textbooks (such as Sabiston, Schwarts). In the present manuscript we report two cases of bladder rupture with iatrogenic and spontaneous origin and suggested that bladder rupture has to be considered in the differential diagnosis of acute abdomen. We evaluated the importance of the physical examination, laboratory findings and imaging modalities in the diagnosis of bladder rupture. The authors think that presentation of these cases were interesting, because we have found only 4 cases published in the literature which report the presence of urinary bladder rupture as a cause of pneumoperitoneum were found. We discussed the importance of pneumoperitoneum in the differential diagnosis in rupture of urinary bladder.