Objectives. To compare the Mortality in Emergency Department Sepsis (MEDS), Sepsis-related Organ Failure Assessment (SOFA), Acute Physiology and Chronic Health Evaluation (APACHE II), and Confusion, Urea, Respiratory rate, Blood pressure, 65 years of age and older (CURB-65) scoring systems for predicting mortality and complications in septic patients. Materials and methods. A prospective study of diagnostic test assessment was carried out. Scores were compared by analysis of receiver operating characteristic (ROC) curves corresponding to each score, with the development of death or complications as the dependent variable. Results. There were 265 patients included in the analysis; 155 (58.4%) patients died and/or presented complications. The multivariate analysis revealed variables associated with mortality and complications were age, oliguria, mental health impairment, acute lung injury, and the use of inotropes. Analysis of ROC curves showed the area below the ROC curve was 0.74 (95% CI: 0.68-0.80) for SOFA, 0.73 (95% CI: 0.67-0.79) for MEDS, 0.73 (95% CI: 0.66-0.79) for APACHE II, and 0.67 (95% CI: 0.60-0.73) for CURB-65, the latter being significantly lower than the first three. Conclusions. The MEDS, SOFA, and APACHE II are adequate scoring systems for predicting mortality and complications in septic patients. It is essential to utilize these scoring systems in emergency medical assistance in hospitals in Peru.