['β-Blockers (BB) are a mainstay of heart failure (HF) treatment, yet there are inconclusive data regarding their efficacy in African American individuals.', 'We performed a retrospective study of insured patients who received care from a large health system who were hospitalized for HF between January 2000 and June 2008 and had a documented ejection fraction <50%. BB exposure was estimated over 6-month rolling windows, using pharmacy claims data. Proportional hazards regression was used to test the association between BB exposure and all-cause hospitalization or death with adjustment for baseline covariates and other HF medication exposure. We performed analyses stratified by race and overall with a BB exposure×race interaction term. A total of 1094 patients met inclusion criteria (476 white and 618 African American individuals). Median follow-up was 2.1 years. In adjusted models, BB exposure was associated with lower risk of death or hospitalization in both groups, but more so in white individuals (hazard ratio, 0.40; 95% confidence interval, 0.27, 0.60; P<0.001) compared with African American individuals (hazard ratio, 0.67; 95% confidence interval, 0.48, 0.94; P=0.024). A formal test for interaction indicated that the protection association for BB exposure differed by race (P=0.098, β=0.40). Reanalysis restricted to BBs approved for HF or HF-specific hospitalizations did not substantively alter the findings.'] Does association of β-blocker exposure with outcomes in heart failure differ between African American and white patients?