Prediction of serious complications is an essential part of risk management in surgery. Knowing which patient to operate and those at high risk of dying contributes significantly to the quality of surgical care and cost reduction. The postoperative mortality of patients who underwent laparotomy in Mulago Hospital was studied using Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity (POSSUM). Consecutive patients who underwent laparotomy in Mulago Hospital were recruited and consent obtained. Patients operated were followed up to the 30th postoperative day. Postoperative deaths were promptly investigated and findings recorded. Follow-up of patients was conducted by phone and surgical review once a week in outpatient. Ethical approval was obtained from the Institutional Review Board (IRB) of Makerere University Medical School. Seventy-six patients participated and the observed mortality was 14.5% and the predictive value of POSSUM using Receiver Operative Characteristics (ROC) curve was 0.817 (95% Confidence Interval 0.711, 0.924) and the Hosmer and Lemeshow test predicted 18.2% of mortality and survival 100%. Postoperative mortality can be predicted in the modern management of surgery using POSSUM. It is markedly influenced by the preoperative, operative and postoperative conditions of the patients.