In a period of 4 years in the Clinic of Abdominal- and Transplantationsurgery of the Medical School Hannover 63 combined surgical procedures were performed in 56 patients with operations of colon and rectum. In comparison with a group of patients, who were treated with similar operations as a single procedure, the increase of risk was studied. Small combined procedures like appendectomia, herniotomia, exstirpation of cysts or removal of diverticula indicate no elevation of the operative risk. Cholecystectomy or prostatectomy, though increasing the entire trauma of operation, did not elevate the rate of complications significantly. In accordance with our results outlines regarding the performance and indication of operations in combination with colon- and rectum surgery are discribed.