Purpose: This study was aimed to compare the quick Sequential Organ Failure Assessment (qSOFA), Systemic Inflammatory Response Syndrome (SIRS), and National Early Warning Score (NEWS) scoring systems for diagnosing sepsis and predicting mortality and morbidity. Patients and methods: A prospective study was designed. qSOFA, SIRS, and NEWS scores were calculated at the admission. The diagnosis of sepsis was made with SOFA scoring initially. The morbidity and mortality of the patients were identified during follow-up. Also, the sensitivity, specificity, negative predictive value, and positive predictive value of three scoring systems were calculated. The scoring systems were compared with ROC analysis. Results: A total of 463 patients were evaluated. There were 287 (62.0%) patients diagnosed with sepsis, and septic shock occurred in 64 (13.8%) of patients. Seven-day mortality rate was 8.4% (n = 39), 30-day mortality rate was 18.1% (n = 84). The sensitivity for qSOFA, SIRS, and NEWS for diagnosis of sepsis was 23%, 77%, 58%, and specificity was 99%, 35%, 81% respectively. The sensitivity of the qSOFA, SIRS and NEWS scoring systems for mortality was 39%, 82%, 77% and specificity 91%, 29%, and 64%, respectively. AUROC values for mortality detected as NEWS = 0.772, qSOFA = 0.758, SIRS = 0.542. According to the ROC analysis, the SIRS system was significantly less useful than the qSOFA and NEWS system in the diagnosis of sepsis and mortality (p < 0.0001). Conclusion: NEWS and qSOFA scoring systems have similar prognosis in both diagnosing sepsis and predicting mortality and both are superior to SIRS. (c) 2021 Elsevier Inc. All rights reserved.