BACKGROUND: The prevalence and prognostic value of overt disseminated intravascular coagulation (DIC) in patients with septic shock presenting to emergency departments (EDs) is poorly understood, particularly following the release of a new definition of septic shock. The purpose of this study was to investigate the prevalence and prognostic value of DIC in septic shock. METHODS: We performed retrospective review of 391 consecutive patients with septic shock admitting to the ED of tertiary care, university-affiliated hospital during a 16-month. Septic shock was defined as fluid-unresponsive hypotension requiring vasopressor to maintain a mean arterial pressure of 65 mmHg or greater, and serum lactate level ≥ 2 mmol/L. Overt DIC was defined as an International Society on Thrombosis and Hemostasis (ISTH) score ≥ 5 points. The primary endpoint was 28-day mortality. RESULTS: Of 391 patients with septic shock, 290 were included in the present study. The mean age was 65.6 years, the 28-day mortality rate was 26.9%, and the prevalence of overt DIC was 17.6% (n = 51) according to the ISTH score. The median DIC score was higher in non-survivors than in survivors (5.0 vs. 2.0, p = 0.001). Significant higher risk of mortality was observed in overt DIC patients compared to those without (28.2% vs. 13.7%, p = 0.005). Multivariable logistic regression analysis identified DIC to be independently associated with 28-day mortality (odds ratio, 2.689 [95% confidence interval, 1.390-5.201]). CONCLUSIONS: Using the ISTH criteria of DIC, overt DIC in septic shock was found to be common among patients admitting to the ED and to be associated with higher mortality when it is accompanied with septic shock. Efforts are required to identify presence of overt DIC during the initial treatment of septic shock in patients presenting the the ED.