We hypothesized that increasing anger verbal behavior in an assertive, constructively motivated style should decrease resting blood pressure (BP) and that this behavior may be one mechanism through which hostility relates to BP. We tested this hypothesis by conducting secondary analyses on a single-blind, matched, randomized controlled study of hostility modification and BP. A total of 22 high-hostile male patients with coronary heart disease were matched on age and hostility level and were randomly assigned to either an 8-week cognitive-behavioral hostility treatment (n = 10) or an information-control group (n = 12). Patients were reassessed after treatment and at 2-month follow-up on hostility, observed anger expression, and resting BP. We found that decreases in hostility predicted increases in constructive anger behavior-verbal component, which in turn predicted decreases in resting BP at follow-up. Thus, one of the mechanisms underlying the hostility-BP association may be the lack of constructive anger expression.