Patients with unstable angina pectoris who remain symptomatic at rest after hospitalization are at increased risk of death or myocardial infarction. This report presents the results of adding the calcium influx blocking agent nifedipine to aggressive therapy with nitrates and beta-blocking drugs in 47 hospitalized patients. The patients were followed up for an average of 12 months. Twenty-two (47%) improved sufficiently to be discharged; despite this symptomatic improvement, 8 had cardiac events within 4 months. Eighteen patients had no symptomatic improvement and 7 of them had cardiac events in 4 months. In 7 others, relief was insufficient to permit discharge, and 1 of these patients had myocardial infarction. In all, 31 patients were treated with medical therapy only. Twenty-one of these patients had a favorable short-term response to nifedipine; 13 died or had an infarction in less than 4 months. Two of 16 patients who underwent coronary artery bypass surgery had cardiac events. The presence of electrocardiographic changes with pain did not identify either a group at higher risk or a group with a better outcome with nifedipine. We conclude that in a high-risk subset of patients with unstable angina pectoris, nifedipine does not reduce morbidity or mortality or the need for bypass surgery, but relieves symptoms in many patients. An early symptomatic response to nifedipine did not predict a reduced incidence of subsequent cardiac events.