To evaluate whether a continuous high blood pressure (BP) monitoring and referral program conducted by barbers motivates male patrons with elevated BP to pursue physician follow-up, leading to improved HTN control, a cluster randomized trial (BARBER-1) of HTN control was conducted among black male patrons of 17 black-owned barbershops in Dallas County, Texas (March 2006-December 2008). Participants underwent 10-week baseline BP screening, and then study sites were randomized to a comparison group that received standard BP pamphlets (8 shops, 77 hypertensive patrons per shop) or an intervention group in which barbers continually offered BP checks with haircuts and promoted physician follow-up with sex-specific peer-based health messaging (9 shops, 75 hypertensive patrons per shop). After 10 months, follow-up data were obtained. The primary outcome measure was change in HTN control rate for each barbershop. The HTN control rate increased more in intervention barbershops than in comparison barbershops (absolute group difference, 8.8% [95% confidence interval (CI), 0.8%-16.9%]) (P = .04); the intervention effect persisted after adjustment for covariates (P = .03). A marginal intervention effect was found for systolic BP change (absolute group difference, -2.5 mm Hg [95% CI, -5.3 to 0.3 mm Hg]) (P = .08).