CT scan is the gold standard for follow-up after abdominal surgery and diagnosis of postoperative complications. During the immediate postoperative period, asymptomatic and rapidly regressing peritoneal collections of fluid and gas are often present. Transient ileus is classically present as well. The diagnosis of postoperative peritonitis is difficult on imaging; fluid collections are frequent and easily detected. The main postoperative peritoneal complication is small bowel obstruction, either early and due to inflammatory changes, or delayed and due to adhesions or less frequently to other causes, including transmesenteric hernia. Other rare complications include desmoid tumors and gossypiboma. Wall complications, after laparotomy as well as laparoscopic surgery, are mainly hematoma, infections and wound hernia.