Pneumoperitoneum is one of the first signs of perforation of the colon wall as a complication after colonoscopy. In a small percentage of cases, pneumoperitoneum is not associated with perforation but microperforation or, what is most interesting, transmural passage of air into the peritoneal cavity. Asymptomatic pneumoperitoneum without peritonitis is called "benign pneumoperitoneum". Because of the difficult underlying causes and a low number of cases, it raises a controversy as to the management. This article describes a case of a woman with pneumoperitoneum and subcutaneous emphysema of the abdomen and neck after colonoscopy. Exploratory laparotomy did not show gastrointestinal perforation.