Mycophenolate mofetil (MMF) has no known nephrotoxicity. This report examines the outcome in patients who received MMF for renal impairment on tacrolimus-based immunosuppression. From 1995 to 1996, twelve liver transplantation (LTx) patients (mean age 54.6 years) with serum creatinine >1.8 mg/dl were included in the study. MMF was introduced and tacrolimus dose was reduced by 30-50%. Each patient was followed for 6 years. Renal function showed improvement in seven patients, deterioration in four, and no change in one patient. Overall mean serum creatinine decreased from 2.5 to 1.9 mg/dl at 6 months but increased to 2.2 mg/dl at 18 to 24 months. After that, renal function remained stable for 72 months. Iothalamate clearance showed 18.5% improvement at 1 year. Three patients developed renal failure. Six patients died in the follow-up period. Addition of MMF with reduced tacrolimus dose resulted in sustained improvement in renal function in 58% of patients.