Coronary artery disease is a frequent complication of end-stage renal disease (ESRD). ST segment depression on ambulatory electrocardiography without patient awareness is a marker of what has been termed "silent ischemia". It has been suggested that in patients with coronary artery disease these transient ST segment depressions are associated with increased cardiovascular mortality. Up to 30% of patients with ESRD may display transient ST segment depression, however the significance of this finding in these group of patients who frequently have associated LV hypertrophy, and rapid electrolyte changes has not been clear. We therefore set out to determine the incidence of transient ST segment depression during ambulatory Holter monitoring in 70 consecutively studied hemodialysis patients. Sixty-seven patients wore the monitor for at least 12 hours and 16 patients (23%) demonstrated at least one minute of 1 mm ST segment depression. The presence of clinically apparent coronary artery disease, diabetes, left ventricular hypertrophy, sex or race were not significantly associated with the probability of demonstrating transient ST segment depression. The survival of patients with or without transient ST segment depression was the same at 2 years with 70% of patients remaining free of death, nonfatal myocardial infarction, or coronary bypass grafting. We conclude that patients with ESRD frequently demonstrate transient ST segment depression, however, the presence of these findings on ambulatory Holter monitoring does not appear to be associated with increased long-term mortality.