The pilot study of the Systolic Hypertension in the Elderly Program was a randomized, double‐blind, placebo‐controlled trial of drug therapy for isolated systolic hypertension. It followed 551 elderly participants with untreated blood pressures of >160/< 90 mm Hg for an average of 34 months. Mean age of the participants was 72 years; 63% were women, and 82% were white. Pretreatment blood pressures averaged 172/75 mm Hg. Participants were randomly assigned to treatment with chlorthalidone or placebo as Step I medication. Blood pressures at annual visits averaged 141/68 and 157/73 mm Hg for the drug‐treated and placebo‐treated groups, respectively, with 60% and 33% of the survivors on blinded medication having systolic blood pressures of < 160 nun Hg at their last annual visit. All‐cause mortality rates for the drug‐treated and placebo‐treated groups were 25.4 and 22.7 deaths per 1,000 participant‐years of risk, and rates for definite “first stroke” were 8.3 and 12.8 per 1,000 years of risk. Differences between groups were significant for systolic and diastolic blood pressure but not for death or stroke rates. A full‐scale study has begun to determine the effects of drug therapy for isolated systolic hypertension on stroke and mortality rates. (Stroke1989;20:4–13)