OBJECTIVE To determine wether the physical status (ASA category) and surgical conditions could predict mortality in elderly general surgery patients. METHODS This was a prospective study of patients greater than or equal 85 years of age who underwent elective or emergency surgery under general anesthesia between January 1987 and December 1991. Hospital mortality was defined as death occurring before discharge. Logical regression analysis (Cox's modeling) was used to assess group survival. RESULTS One hundred and nine patients undergoing 117 operations were enrolled. Major surgery was performed in 70%; 44% were removals of malignant tumors and 84% were under general anesthesia. Hospital deaths occurred in 10%; the only significant predictors were neoplastic disease and emergency status. Mortality was 43% one year after surgery; significant predictors of death were prior physical status, neoplasia and emergency status. CONCLUSIONS Neoplastic disease, emergency status and poor physical condition are factors that predict mortality in patients 85 or older who undergo general surgery.