To assess whether increased use of targeted temperature management (TTM) within an integrated healthcare delivery system resulted in improved rates of good neurologic outcome at hospital discharge (Cerebral Performance Category score of 1 or 2). Retrospective cohort study of patients with OHCA admitted to 21 medical centers between January 2007 and December 2012. A standardized TTM protocol and educational program were introduced throughout the system in early 2009. Comatose patients eligible for treatment with TTM were included. Adjusted odds of good neurologic outcome at hospital discharge and survival to hospital discharge were assessed using multivariate logistic regression. A total of 1119 patients were admitted post-OHCA with coma, 59.1% (661 of 1119) of which were eligible for TTM. The percentage of patients treated with TTM markedly increased during the study period: 10.5% in the years preceding (2007-2008) vs. 85.1% in the years following (2011-2012) implementation of the practice improvement initiative. However, unadjusted in-hospital survival (37.3% vs. 39.0%, p=0.77) and good neurologic outcome at hospital discharge (26.3% vs. 26.6%, p=1.0) did not change. The adjusted odds of survival to hospital discharge (AOR 1.0, 95% CI 0.85-1.17) or a good neurologic outcome (AOR 0.94, 95% CI 0.79-1.11) were likewise non-significant. Despite a marked increase in TTM rates across hospitals in an integrated delivery system, there was no appreciable change in the crude or adjusted odds of in-hospital survival or good neurologic outcomes at hospital discharge among eligible post-arrest patients.