To determine prognostic factors associated with mortality in patients aged 80 years and over who were treated at the Department of Surgery within a one-year period.Prospective.The following items from the complications register were investigated: degree of mobility prior to the operation and the housing circumstances, presence of comorbidity in the case history (heart disease, lung disease, diabetes mellitus, dementia, urgency of admission and operation (elective, urgent, acute)), and the surgical subspecialism (gastroenterology, traumatology, vascular surgery and general surgery). The number of postoperative complications was also examined. Statistical analyses were performed using the chi 2 test and multiple logistic regression analysis.A total of 179 patients were included: 53 men and 126 women, with an average age of 85 years and 86 years respectively. The overall mortality was 11%: 39% in acutely presented patients and 8% in subacute patients. None of the electively operated patients died. The following factors were significantly associated with mortality: subacute presentation (odds ratio 8.5; 95%-CI: 2.8-27), acute presentation (odds ratio 72; 95%-CI: 8-737), cardiological evaluation without further measures was associated with less mortality (odds ratio 0.13; 95%-CI: 0.02-0.85).The risk of mortality increased with the urgency of presentation. A cardiological evaluation in which the patient, without the need for further additional measures, was found to be in an optimal condition was associated with a relatively low risk of mortality.