The purpose of the present study is to assess the safety of enalapril, a drug in the ACEI class, when started 1-3 month post transplant. This is a double-blinded, randomized control trial of enalapril vs. placebo in new renal transplant patients with serum creatinine values no higher than 2.5mg/dl and normal serum potassium levels. The study drug will be administered for 6 months. Patients will be monitored in the renal transplant clinic every 1-4 weeks according to routine protocol. Clinical end-points will be occurence of potassium >5.9mEQ/L or sustained increase in serum creatinine >50% from baseline.