BACKGROUND: Less than one third of the 65 million Americans with hypertension have adequate blood pressure (BP) control. This study examined the effectiveness of 2 interventions for improving patient BP control. METHODS: This was a 2-level (primary care provider and patient) cluster randomized trial with 2-year follow-up occurring among patients with hypertension enrolled from a Veterans Affairs Medical Center primary care clinic. Primary care providers (n = 17) in the intervention received computer-generated decision support designed to improve guideline concordant medical therapy at each visit; control providers (n = 15) received a reminder at each visit. Patients received usual care or a bimonthly tailored nurse-delivered behavioral telephone intervention to improve hypertension treatment. The primary outcome was proportion of patients who achieved a BP <140/90 mm Hg (<130/85 for diabetic patients) over the 24-month intervention. RESULTS: Of the 816 eligible patients contacted, 190 refused and 38 were excluded. The 588 enrolled patients had a mean age of 63 years, 43% had adequate baseline BP control, and 482 (82%) completed the 24-month follow-up. There were no significant differences in amount of change in BP control in the 3 intervention groups as compared to the hypertension reminder control group. In secondary analyses, rates of BP control for all patients receiving the patient behavioral intervention (n = 294) improved from 40.1% to 54.4% at 24 months (P = .03); patients in the nonbehavioral intervention group improved from 38.2% to 43.9% (P = .38), but there was no between-group differences at the end of the study. CONCLUSION: The brief behavioral intervention showed improved outcomes over time, but there were not significant between group differences.