Hypertension is one of the most common diseases seen by the practicing physician. Yet, because of noncompliance, conditions of many hypertensive patients are not effectively controlled by treatment. The purpose of this study was to test the efficacy of a patient education program in reducing the blood pressure (BP) of hypertensive patients in a private, solo medical practice. The intervention program focused on three behavioral objectives - pill taking, appointment keeping, and dietary sodium reduction while stressing the need for taking responsibility for one's own care. It was hypothesized that patients receiving an educational intervention stressing self-care would benefit more than those receiving the usual medical care. A substantial reduction in BP was considered to be the measure of successful treatment. Thirty-nine hypertensive patients receiving drug therapy from a private, solo medical practice were randomized into either a treatment group or a control group. A comparison of means disclosed no pretreatment differences between the groups' average BPs. After following up both groups for 6 months, mean changes in BP were compared for both treatment and control patients using a two-sample t test for independent samples. The BP fell in the treatment group (-13 mm Hg, systolic; -8 mm Hg, diastolic) but rose slightly in the control group (3 mm Hg, systolic; 0.5 mm Hg, diastolic). The difference in changes was significant for both the systolic and diastolic BP.