One hundred and six patients found at operation to have intra-abdominal sepsis were prospectively followed up to determine the incidence of organ malfunction and death. These outcomes were correlated with age, preexisting disease, underlying cause of sepsis, shock, nutritional status, and alcoholism. Organ malfunction occurred in 31 patients (29%), 19 (61%) of whom died. Two (3%) of 75 patients without organ malfunction died. Discriminant analysis revealed a significantly increased risk of death in patients with shock at any time, age greater than 65 years, alcoholism, bowel infarction, or malnutrition. A discriminant equation based only on preoperative variables correctly assigned the outcome of death or survival in 97 (92%) of the patients based on probabilities derived from this analysis. At present, this information is primarily of interest for researchers comparing outcomes in groups of patients, but with additional refinements it may become clinically useful for individual patients.