Differences in the quality of medical care provided to black and white patients have been observed in the United States, but have not been studied in dialysis patients. We examined whether dialysis delivery, as measured by indirect determination of Kt/V, differs between black and white patients in New Jersey. Five hundred forty-four patients at 10 New Jersey dialysis units were randomly selected by the US Health Care Financing Administration as part of their Medical Case Review Study. Of these, 237 patients at eight units were classified as black or white and had urea kinetic data available. The mean Kt/V urea was higher for white than black patients at all facilities, averaging 1.03 for the 123 black patients and 1.20 for the 114 white patients (P = 0.0006). Black patients were 40% more likely than white patients to have a Kt/V less than 1.0 (45.6% of black patients v 32.5% of white patients, P = 0.038). Racial disparities in dialysis delivery exist, the causes and consequences of which need to be addressed.