Scoring systems such as POSSUM and P-POSSUM have been developed to help predict mortality and morbidity in patients. The ratio of observed-to-predicted (O/P ratio) mortality and morbidity has been used as a performance indicator to compare different procedures, clinicians or hospitals. The aim of this study was to assess the predictive value of POSSUM compared with P-POSSUM in patients undergoing laparotomy in Queen Elizabeth Hospital, Sabah.