Pneumoperitoneum is abnormal presence of air or any other gas in the peritoneal cavity. This finding can be both benign or a sign of a grave underlying pathology and a wide spectrum of clinical conditions can attribute to the finding. Prompt clinical examination of a case of abdominal pain can identify findings of peritonitis. We are reporting an interesting case report about a patient of acute abdomen with pneumoperitoneum and peritonitis which was caused by spontaneous rupture of urinary bladder. A 36-year-old male, came with complaints of abdominal pain for one day, two episodes of non-bilious vomiting. He was a known case of neurogenic bladder on continuous bladder drainage. Systemic examination of the abdomen showed warmth, diffuse tenderness, guarding and absent bowel sounds. Bladder catheterisation showed clear urine. On investigation, He had pneumoperitoneum in chest X-ray and free fluid in ultrasonography. A clinical diagnosis of hollow viscus perforation was made and emergency laparotomy was done in view of signs of peritonitis. There was rupture of the dome of urinary bladder with necrosis of the bladder wall and extravasation of urine into the peritoneal cavity. This rare presentation should remind us to keep all the differential diagnoses in mind while opening a case of perforation peritonitis as timely intervention can well and truly be the difference between life and death.