We compared short-term heart rate variability (HRV) in 60 patients with end-stage renal disease (ESRD) with 33 age-matched healthy controls and also assessed the contribution of known determinants of HRV in the ESRD patients. HRV was markedly decreased in the ESRD patients and the predictor variables of cardiac diseases, diabetes mellitus, age, heart rate, gender, and smoking explained only a small portion of HRV, suggesting that ESRD itself is an independent factor for decreased HRV.