The aim of this study was to evaluate the prevalence of restless legs syndrome (RLS) in patients with end-stage renal disease (ESRD), and to determine its association with sleep disorders and premature discontinuation of dialysis ("sign-offs"). End-stage renal disease patients (N = 204) and a control group of patients with heart disease (N = 129) completed a self-administered questionnaire regarding symptoms of RLS, sleep habits, pruritus, and adherence to dialysis therapy. Laboratory measures and sensory nerve amplitudes were collected on the ESRD patients. Twenty percent of the ESRD patients and 6% of the cardiac patients reported moderate to severe RLS symptomatology. Sleep onset was delayed and total sleep time was diminished in ESRD patients compared with cardiac patients. Symptoms of RLS were directly correlated with all sleep measures as well as with pruritus. Symptoms of RLS, sleep onset latency, and transferrin saturation were independently associated with premature discontinuation of dialysis. Significantly increased risk for mortality was observed in patients with RLS at the 2.5-year follow-up. Restless legs syndrome is a common finding in patients with ESRD and is associated with substantial morbidity.