In this study, we evaluate independent key prognostic factors of patients who managed with septic shock in the emergency department. This was a retrospective study through chart review of emergency medical records of all patients over eighteen years old who managed and hospitalized from emergency department with septic shock from January 2008 to September 2014 at one regional emergency center in South Korea. The primary outcome was mortality at 30 days after ED arrivals and secondary outcomes were length of intensive care units (ICU) stays, day supported by ventilators, and hospitalized days. Of 648 patients admitted from ED during study period, 187 patients (28.9%) were dead. Factors associated with 30 days mortality in multiple logistic analysis were elderly patients (>70 years) (adjusted odds ratio〔 OR〕2.24, 95% confidence interval〔 CI〕1.39-3.63), leukopenia (white blood cell count < 4,000 /mm3) (2.91 OR, 1.34-6.34 95% CI), prolonged international normalized ratio (INR) over 1.2 (1.71 OR, 1.06-2.76 95% CI), respectively. About 28.9% of patients with septic shock in one emergency center were dead, and several prognostic factors figured out by multiple logistic regression analysis including lactate levels at arrivals in ED over 4 mmol/ L. And also lactate levels associated with duration of ICU care among survivors.