The incidence of complications in a consecutive series of 515 abdominal surgical operations was studied. Abdominal complications of varying degree of severity were observed in 62 cases (16%). They were of four types: haemorrhage, ileus, peritonitis and complications on the part of the biliary tract and pancreas. The use of radiological methods for detecting these complications is reviewed. Direct roentgenography is the method of choice in cases of suspected ileus, perforation or foreign body. Administration of contrast media should be reserved almost entirely to cases of stress ulcer and to distinguish between incomplete and complete ileus. If perforation of penetration is suspected only water-soluble contrast media should be used. Detection of a leaking anastomosis or an abscess is by injection of the fistula. The value of angiography for revealing a haemorrhage or embolism and for assessing the response to vasoactive agents is discussed.