Heroin-associated nephropathy (HAN) is a common cause of end-stage renal disease (ESRD) among 18- to 45-year-old patients in the Buffalo area. To assess the importance of HAN nationwide, a questionnaire was sent to 130 dialysis units or sections of nephrology throughout the United States. Fourteen metropolitan areas represented by 23 respondents reported 98 cases of HAN. Ninety-two patients (93.9%) were black. Black men made up the single largest group, with 77 patients (78.6%). The ESRD had already developed in 66 (67.3%) of the patients with HAN. The occurrence of HAN was high in those units that responded to the questionnaire. These figures, however, do not represent the prevalence of HAN in the United States. The economic impact of treating HAN may be striking. The estimated cost of maintaining just the 66 addicted patients with renal failure on dialysis would be greater than $ 1 million yearly.