POSTOPERATIVE SURVIVAL AMONG NONAGENARIANS. A RETROSPECTIVE STUDY Background: As the Chilean population ages, anesthesiologists are regularly faced with elderly and even nonagenarian people undergoing surgical procedures. Aim: To determine the postoperative survival time in nonagenarians and its risk factors at a private clinic. Material and methods: Review of medical records of the clinic, searching for patients aged 90 years old or more, which were subjected to a surgical procedure between 2001 and 2012. Certification of survival or death was obtained from the clinical records or death certification at the National Identification Service. Survival analysis was made using Kaplan-Meier and Gompertz regression. Results: The medical records of 167 patients, aged 90 to 101 years (64% women), were reviewed. Sixty four percent had an underlying cardiovascular disease in 37%, cognitive impairment. Hip fracture surgery was the most common procedure. One intraoperative death occurred. Five percent of patients died one month after surgery. The median survival time was two years and the longest, seven years. According to Gompertz probability regression, the predictors of death were the presence of cardiac disease (Hazard ratio (HR): 1.91, 95% confidence intervals (95%CI): 1.16; 3.16), cognitive impairment (HR: 2.10, 95%CI: 1.32; 3,22 ), cancer (HR:2.10, 95%CI:1.32; 3.22), requirement of transfusion (HR: 1.79, 95%CI: 1.13; 2.83) and an American Society of Anesthesiologists (ASA) Class III classification (HR: 1.95, IC95%: 1.21; 3.15)  Conclusions: In nonagenarian patients undergoing surgery; 50% mortality was observed 2 years after surgery. The presence of cardiac disease, cognitive impairment, cancer, transfusion and a Class III ASA classification were predictors of death.