Diabetes mellitus has been suggested as a risk factor in patients undergoing gallbladder surgery. To assess the validity of this observation, a study of 175 diabetic and nondiabetic patients who underwent cholecystectomy of cholecystostomy was undertaken. Eighty patients (40%) were diabetic, and 95 (54%) were nondiabetic. The rates of death and complications were nearly identical in both diabetic and nondiabetic populations. In this selected population renal disease and vascular occlusive disease (with or without diabetes mellitus) resulted in a significant (P less than 0.01) increase in morbidity and mortality rates. Therefore, we conclude that diabetes mellitus alone does not appear to adversely affect the prognosis of patients who require gallbladder surgery.