The clinical efficacy of vasodilator therapy in the treatment of chronic congestive heart failure specifically in the elderly population has not been previously reported. Fifteen patients age 71 to 91 years with symptomatic heart failure were given vasodilator in addition to a digitalis and diuretic regimen. Seven received hydralazine 100-400 mgms. per day plus nitrates and 8 were treated with prazosin 6-60 mgms. per day, 6 of whom received additional nitrates. Initial systolic blood pressure was 130-220 mm Hg (166 +/- 25.3). This gradually fell with recurrent failure and increasing doses of medications. Heart rate remained relatively unchanged. Side effects were similar to these reported in younger patients. The only serious incident occurred in the one patient receiving minoxidil when aggressive angina developed culminating in nonfatal myocardial infarction. Implications and possible precautions are discussed. Duration of effectiveness was variable but a program of evaluation by nurses at home often allowed for early recognition of decompensation. Readjustment of medication commonly alleviated symptoms, increased exercise tolerance and decreased the frequency of rehospitalization.