African Americans have a higher prevalence of hypertension and poorer cardiovascular and renal outcomes than white Americans. The objective of this study was to determine whether a telephonic nurse disease management (DM) program designed for African Americans is more effective than a home monitoring program alone to increase blood pressure (BP) control among African Americans enrolled in a national health plan. A prospective randomized controlled study (March 2006-December 2007) was conducted, with 12 months of follow-up on each subject. A total of 5932 health plan members were randomly selected from the population of self-identified African Americans, age 23 and older, in health maintenance organization plans, with hypertension; 954 accepted, 638 completed initial assessment, and 485 completed follow-up assessment. The intervention consisted of telephonic nurse DM (intervention group) including educational materials, lifestyle and diet counseling, and home BP monitor vs. home BP monitor alone (control group). Measurements included proportion with BP < 120/80, mean systolic BP, mean diastolic BP, and frequency of BP self-monitoring. Results revealed that systolic BP was lower in the intervention group (adjusted means 123.6 vs. 126.7 mm Hg, P = 0.03); there was no difference for diastolic BP. The intervention group was 50% more likely to have BP in control (odds ratio [OR] = 1.50, 95% confidence interval [CI] 0.997-2.27, P = 0.052) and 46% more likely to monitor BP at least weekly (OR 1.46, 95% CI 1.07-2.00, P = 0.02) than the control group. A nurse DM program tailored for African Americans was effective at decreasing systolic BP and increasing the frequency of self-monitoring of BP to a greater extent than home monitoring alone. Recruitment and program completion rates could be improved for maximal impact.