Background: Sepsis is a life threating medical condition where infection leads to massive inflammatory response and eventually lead to organ dysfunction. It continues to pose a significant health threat despite remarkable developments in critical care medicine and extensive study of septic patients. Early recognition and treatment of sepsis in emergency department (ED) is important to reduce mortality, hospital length of stay and morbidity. Objective: This study was aimed to validate the performance of qSOFA scoring system and SIRS criteria in early sepsis diagnosis in the Emergency Department. Patient and method: This prospective observational clinical study was carried out in Emergency Department (ED) on 100 patients with suspected infection presented and admitted at o Mansoura University Emergency Hospital from February 2019 to February 2020. Patients were divided into two groups: infection group with qSOFA –ve criteria and sepsis group with qSOFA +ve group. We compare between qSOFA and SIRS scores in both groups. Results: The study demonstrated that organ dysfunction >2, 2ry to infection (according to sepsis definition by sepsis-3 task force) was more frequently reported among qSOFA + SIRS + group, compared to qSOFA - SIR – group. Moreover, both qSOFA and SIRS had comparable sensitivity (100%) in prediction of mortality within 1 week, while qSOFA demonstrated higher specificity (53.3%) in comparison with SIRS (20%). Both scores had comparable sensitivity for prediction ICU admission and of mechanical ventilation (86.67 and 88.9) whereas qSOFA demonstrated higher specificity than SIRS for ICU admission (94.29 versus 71.43) as well as mechanical ventilation (82.9 versus 63.41). Conclusion: It could be concluded that qSOFA is considered as specific not sensitive tool, while SIRS is more sensitive but not specific score for sepsis detection in emergency room.