In a retrospective study 403 patients with colorectal carcinoma and elective gut resection were investigated with respect to postoperative complications and mortality depending on the age and accompanying risk factors (pulmonary diseases, cardiac diseases, diabetes mellitus, renal failure, arterial circulatory disturbances). Postoperative mortality was 1.3% in younger patients ( 75 years). In the presence of one risk factor none of the younger but 10% of the older and old patients died postoperatively. In the presence of two or more risk factors mortality was 0, 12.5 and 15%, respectively. In a multivariate analysis age alone showed no statistically significant influence on the lethal outcome. The important fact for the higher mortality not only in the old but already in the older patients was the presence of risk factor