Background: In this study, we evaluated the prognostic factors in patients with septic shock who were managed at an Emergency Department (ED). Methods: This retrospective study was conducted through a chart review of the emergency medical records of all patients with septic shock who were over 18 years of age and managed and hospitalized in the ED from January 2008 to September 2014 at 1 regional emergency center in South Korea. The outcome sought was mortality at 30 days after ED arrival. Results: Of the 648 patients admitted to the ED during the study period, 187 patients (28.9%) died. Factors associated with 30-day mortality in a multiple logistic regression analysis were elderly patients (>70 years), acute physiology and chronic health evaluation II, leukopenia (white blood cell count<4,000/mm 3 ), prolonged international normalized ratio above 1.2, hypoxemia (pO2<83 mmHg), lactate level (>4.0 mmol/L), pneumonia-related sepsis, and history of tuberculosis, respectively. Conclusion: An age of over 70 years was related to mortality in septic shock; however, other various laboratory results and biomarkers were also related to mortality and some factors even demonstrated a stronger relationship than age. Treatment should not be limited among elderly septic shock patients due to an ED physician's prejudice. Instead, ED physicians should make decisions regarding the care of septic shock patients by considering various factors including unstable clinical signs, laboratory findings, lactate, and source of infection, in addition to the patient's age, in order to produce better outcomes.