In 16 patients with end-stage renal disease (ESRD), 24-hour electrocardiographic recordings showed an incidence of supraventricular and ventricular arrhythmias similar to that in patients who had had myocardial infarction and in low-risk subjects. Eight patients (50%) with ESRD had supraventricular complexes. This incidence was significantly higher than that after myocardial infarction (P<.001). Fifteen ESRD patients (94%) had premature ventricular complexes (PVCs), including nine (56%) with complex PVCs (multiform PVCs, couplets, or runs). The incidence of PVCs as well as complex PVCs in patients with ESRD was comparable to that of the patients who had had myocardial infarction but was significantly higher than that found in low-risk subjects (P <.005 for PVCs and P <.05 for complex PVCs). The high incidence of complex PVCs in patients with ESRD may predispose them to increased cardiovascular death, and further investigation of this finding is indicated.