The elderly constitute the fastest-growing segment of the end-stage renal disease (ESRD) population, but the epidemiology and outcomes of dialysis among the very elderly, that is, those 80 years of age and older, have not been previously examined at a national level. To describe recent trends in the incidence and outcomes of octogenarians and nonagenarians starting dialysis. Observational study. U.S. Renal Data System, a comprehensive, national registry of patients with ESRD. Octogenarians and nonagenarians initiating dialysis between 1996 and 2003. Rates of dialysis initiation and survival. The number of octogenarians and nonagenarians starting dialysis increased from 7054 persons in 1996 to 13,577 persons in 2003, corresponding to an average annual increase in dialysis initiation of 9.8%. After we accounted for population growth, the rate of dialysis initiation increased by 57% (rate ratio, 1.57 [95% CI, 1.53 to 1.62]) between 1996 and 2003. One-year mortality for octogenarians and nonagenarians after dialysis initiation was 46%. Compared with octogenarians and nonagenarians initiating dialysis in 1996, those starting dialysis in 2003 had a higher glomerular filtration rate and less morbidity related to chronic kidney disease but no difference in 1-year survival. Clinical characteristics strongly associated with death were older age, nonambulatory status, and more comorbid conditions. Survival of patients with incident ESRD who did not begin dialysis could not be assessed. The number of octogenarians and nonagenarians initiating dialysis has increased considerably over the past decade, while overall survival for patients on dialysis remains modest. Estimates of prognosis based on patient characteristics, when considered in conjunction with individual values and preferences, may aid in dialysis decision making for the very elderly.