To determine any adverse effects on cardiac performance resulting from long-term hemodialysis, 10 patients treated for 5 or more years (mean 8.4 years) were evaluated by exercise testing and echocardiography. Treadmill stress testing was performed to exhaustion with EKG monitoring according to the Bruce multistage protocol, while maximum oxygen consumption (VO<sub>2max</sub>) was measured directly. 1 patient had equivocal evidence for myocardial ischemia but did not experience angina. 8 of the 10 subjects had both VO<sub>2max</sub> and echocardiographic indices within the normal range established for large groups of controls. The other 2 had EKG and radiologic evidence of cardiac enlargement and had had sustained hypertension.