The study presents the methodology and selected results of the Lazio Dialysis Registry. The registry, begun in 1994, documents basic demographic data, minimal clinical information and vital status of all end-stage renal disease patients on dialysis treatment in Lazio region. At June 1994 the register included 2834 patients; during the next 12 months, 618 new patients had been notified. In one-year follow-up, among prevalent patients, 308 deaths and 90 renal transplants, and among new patients, 80 deaths and 9 renal transplants were observed. The mean age of the studied population was 59.6 (SD 15.1) for prevalent patients and 61.9 (SD 15.3) for new patients. Among prevalent patients 58.8% were males and 41.2% females, among new patients these figure were 62.1% and 37.9%, respectively. The prevalence rate was 55 per thousand population and the incidence rate was 12.0. The leading cause of renal failure was glomerulonephritis in prevalent patients (27.7%), among new patients the most representative group was nephropathies of unknown origin (27.0%). About 85% were on hemodialysis treatment, and about 4% on peritoneal dialysis. The cumulative survival rates during the one-year follow-up was 81.9%, among patients with age less than 65 years a better survival for males (94.9%) than females (90.1%) was observed. The results of the first year of activity show that a population-based registry of patients on chronic dialysis treatment can be an useful tool for service planning and epidemiological research.