Pneumoperitoneum is associated with a ruptured abdominal viscus in > 90% of occurrences. When peritoneal air exists with trauma, fever, leukocytosis, or signs of peritonitis, it is managed with surgical laparotomy. In 5 to 10% of cases, pneumoperitoneum results from a different pathology. This is designated as nonsurgical, spontaneous, or idiopathic pneumoperitoneum. It usually requires only conservative management. Nonsurgical pneumoperitoneum can be caused by procedures, inflammatory conditions, and infection. Procedural causes include abdominal surgery, peritoneal dialysis, and GI endoscopy. Pneumoperitoneum without bowel perforation occurs > 60% of the time following open abdominal surgery, and 25% of the time after laparoscopic procedures. Following diagnostic colonoscopy, there is free abdominal air < 1% of the time. If a therapeutic intervention is performed, the incidence increases to 3%. Pneumoperitoneum from surgery or intraabdominal procedures will resolve with supportive care in 97% of cases within 5 days.