This study was undertaken to evaluate the effect of increasing the dialysate sodium concentration on myocardial ischemia assessed by EKGs taken immediately before and after dialysis in 43 hemodialysis patients. An increase in the R wave (V5 + V6) by more than 5 mm was seen in 26 patients with standard sodium dialysate, while only 12 cases showed the same changes after a high sodium dialysis. These was a positive correlation between an increase in R wave amplitude and the weight loss/dry weight ratio of patients only after standard sodium dialysis (r = 0.74, p < 0.001). Relative high sodium dialysate is beneficial during dialysis and reduce the incidence of myocardial ischemia and unpleasant disequilibrium syndrome.