Blood pressure (BP) control rates and number of antihypertensive medications were compared (average follow-up, 4.9 years) by randomized groups: chlorthalidone, 12.5-25 mg/d (n=15,255), amlodipine 2.5-10 mg/d (n=9048), or lisinopril 10-40 mg/d (n=9054) in a randomized double-blind hypertension trial. Participants were hypertensives aged 55 or older with additional cardiovascular risk factor(s), recruited from 623 centers. Additional agents from other classes were added as needed to achieve BP control. BP was reduced from 145/83 mm Hg (27% control) to 134/76 mm Hg (chlorthalidone, 68% control), 135/75 mm Hg (amlodipine, 66% control), and 136/76 mm Hg (lisinopril, 61% control) by 5 years; the mean number of drugs prescribed was 1.9, 2.0, and 2.1, respectively. Only 28% (chlorthalidone), 24% (amlodipine), and 24% (lisinopril) were controlled on monotherapy. BP control was achieved in the majority of each randomized group-a greater proportion with chlorthalidone. Over time, providers and patients should expect multidrug therapy to achieve BP <140/90 mm Hg in a majority of patients.