Purpose: We determine the suitability of patients with fibromuscular dysplasia of the renal arteries as renal donors. Materials and Methods: We evaluated 37 patients with fibromuscular dysplasia who were potential renal donors. Renal artery lesions were graded I (mild) to IV (severe). Of the patients 19 underwent donor nephrectomy and 18 were rejected as donors. Reasons for rejection included severity of disease or availability of a better donor. Nephrectomy was performed on the side with fibromuscular dysplasia when disease was unilateral or on the side with more advanced disease when the lesions were bilateral. Patients were followed at 1 month, 1 year and then yearly. Results: Of the 19 patients undergoing donor nephrectomy serum creatinine increased by a mean of 0.4 mg./dl. (range 0.1 to 1.1) on postoperative day 1. Effective renal plasma flow of the remaining kidney increased by 25% on postoperative day 5 and by 29% after 1 year. After a mean followup of 4.5 years no patient had hypertension, proteinuria or any significant change in serum creatinine compared to baseline values. Of the 18 patients not undergoing nephrectomy 11 were contacted at a mean followup of 4 years, and none had hypertension, proteinuria or abnormal serum creatinine. Conclusions: Patients with fibromuscular dysplasia may be acceptable renal donors. The decision to use a patient with fibromuscular dysplasia as a donor is based on patient age, the availability of other suitable donors, and the extent and severity of disease.