Between March 1981 and November 1992, 100 heart-lung transplantations were performed at our institution. We report on the renal function in the 67 patients who survived a minimum of 6 months posttransplantation, and who were aged more than 10 years at the time of transplant. Renal function was determined by serial measurement of serum creatinine. Mean serum creatinine increased from 0.96 ± 0.03 mg/dL at baseline to 1.55 ± 0.07 mg/dL at 6 months posttransplantation, to 1.88 ± 0.11 mg/dL at the end of follow-up (mean follow-up, 50.0 months; range, 6 to 140 months). The decline in renal function was biphasic, with a rapid decrease in the first 6 months, followed by a much slower decline. Three patients developed end-stage renal failure. This compares with 14 of 416 cardiac transplant recipients at Stanford who developed end-stage renal failure over the same period. We conclude that in our large series at a single center the incidence of renal impairment and end-stage renal failure is low and similar between heart-lung and heart transplant patients. © 1995.