Objective: This study aimed to determine whether cardiopulmonary bypass (CPB) resuscitation comparing with conventional cardiopulmonary resuscitation (C-CPR) is associated with improved OHCA outcomes in Korea. Methods: We used a Korean national OHCA cohort database composed of hospital and ambulance data. We included all EMS-treated OHCA with presumed cardiac etiology for the period Jan. 2009 to Dec. 2012 excluding cases without available hospital outcome data. The primary exposure was CPB resuscitation during CPR at emergency department (ED). The endpoints were survival to admission, hospital discharge with brain recovery (cerebral performance category 1 or 2). We compared outcomes between CPB versus non-CBP group using multivariable logistic regression for calculating adjusted odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for individual, Utstein, post-resuscitation factors, and comorbidities. using original and propensity-score matched datasets. Results: Of 93,562 patients with OHCA, we included 55,255 excluding non-treated (n=14,733), non-cardiac (n=23,521), and unknown brain recovery at discharge (n=55). Overall survival to admission and to discharge with good brain recovery was 13.5% and 2.1%, respectively. CPB was performed in 207 (0.4%); 0.1% (2009), 0.2% (2010), 0.4% (2011), 0.7% (2012), respectively. Survival to admission was significantly higher in CPB group (78.3%) than non-CPB (13.3%) in original dataset (Adjusted OR=9.98, 95% CI 7.00-14.24). Discharge with good brain recovery was significantly higher in CPB (9.7%) than non-CPB (2.0%) but adjusted OR (95% CI) was not significant in original dataset; 1.15 (0.62-2.13). From propensity score matched dataset (N=414 from 207 CPB cases and 207 non-CPB cases), survival to admission was significantly higher in CPB group (78.3%) than non-CPB (56.0%) (Adjusted OR=5.37, 95% CI 2.82-10.21). Discharge with good brain recovery was significantly lower in CPB (9.7%) than non-CPB (15.9%) with adjusted OR (95% CI); 0.51 (0.24-1.11). Conclusions: The CPB resuscitation has been increased by year and was associated with higher survival to admission. But it is not associated with hospital discharge with brain recovery in nationwide observational study in Korea.