Malignant tumors are a frequent problem in gerontologic medicine; moreover, the number of geriatric patients is increasing. Surgical treatment is often proposed for solid tumors, even in patients over 80 years of age. 183 cases observed over the last 15 years in the Digestive and Thoracic Clinics of the University Hospital, Geneva, are reviewed. The affected organs were, in order of frequency, 1. large bowel, 2. breast, 3. stomach, and, more rarely, biliary tract, pancreas, esophagus and liver. Postoperative survival was satisfactory in this series. Analysis by organ shows that, in the case of the large bowel, one-stage resection-anastomosis provides the best results. For the breast, the classic procedures under general anesthesia are recommended. For the stomach, resection of the tumor prolongs survival. Postoperative mortality within 30 days is not increased by this type of intervention. Classification of evaluation of operative risk, as proposed by the American Society of Anesthesiologists, corresponds favourably with the postoperative mortality rate. For nearly 60% of our patients the quality of life is the same postoperatively as before. In this group, 78% have a Karnofsky index of 100%. It can therefore be stated that surgery for solid tumors is well tolerated by geriatric patients.