The Beta-Blocker Heart Attack Trial (BHAT) was a multicentered, double-blind, randomized, placebo-controlled clinical trial designed to test the efficacy of long-term therapy with propranolol given to survivors of an acute myocardial infarction (MI). Three thousand, eight hundred and thirty-seven men and women, aged 30-69 years, were randomized into either the propranolol or placebo group 5 to 21 days after hospital admission for the MI and were followed at quarterly visits for 12 to 40 months (mean = 25 months). The primary outcome for the trial was all-cause mortality. This article describes the design and baseline findings of the trial. Included is a description of the historical background for the trial and the procedures employed in patient recruitment, randomization, treatment and follow-up. Also included is a comparison between the BHAT population and post-myocardial infarction patients enrolled in the other long-term trials of beta-blockers.