Background Patients with septic shock have a high mortality. This study used the Surviving Sepsis Campaign (SSC)database to compare characteristics, treatments and outcomes of septic shock patients diagnosed in the emergency department (ED) to patients developing septic shock on hospital floors (HF).Methods The studied population included patients admitted to the intensive care unit (ICU) of an urban tertiary care medical center over an 18-month period. Acute physiology and chronic health evaluation (APACHE Ⅱ) scores, need for mechanical ventilation (MV), performance on four of the SSC resuscitation bundle indicators, ICU length of stay (LOS),hospital LOS and in-hospital mortality were ascertained.Results Sixty-six ED and 27 HF septic shock patients were included in this study. Urinary tract infections (UTI) and pneumonia were the two most common sites of infection in the ED patients. The sources of infection for HF septic shock patients were fairly well distributed across etiologies. The time to achieve superior vena cava oxygen saturation (ScvO2)＞ 70% in HF patients ((10.8±9.1) hours) was longer when compared to the ED patients ((6.6±-6.1) hours) (P ＜0.05).Hospital mortality for the ED and HF patients were 25.8% and 59.3%, respectively (P ＜0.05). Use of MV during the first 24 hours of shock was 44% in the ED patients and 70% in the HF patients (P ＜0.05) and was linked to mortality.Conclusions When compared to HF patients, ED septic shock patients have lower in-hospital mortality, there was less use of MV during the first 24 hours following onset of septic shock and the HF patients required a longer time to achieve target ScvO2. The need for mechanical ventilation is independently associated with increased mortality.