This randomized, comparative study assessed the long-term efficacy and tolerability of thymoglobulin (TMG) induction in 93 liver transplant patients with an initial regimen of tacrolimus (Tac), mycophenolate mofetil (MMF), and steroids. Forty-four patients were randomly allocated to the TMG+ group, and 49 patients were randomly allocated to the TMG- group. In both groups, Tac was given orally at the initial daily dose of 0.075 mg/kg twice daily, and MMF was given at the initial daily dose of 2 g/day. Steroid withdrawal was planned at 3 months after liver transplantation. The results were evaluated with respect to acute rejection incidence, patient and graft survival, graft function, and medical complications until 5 years or death for all patients. No significant differences were found between groups for the incidence of acute rejection at 5 years (11.4% versus 14.3%), 5-year patient survival (77.3% versus 87.8%), graft function, or postoperative renal function. One patient in the TMG- group underwent retransplantation. There was no difference between groups with respect to the incidence of medical complications, excepted for a higher rate of leukopenia in the TMG+ group, during the 5-year follow-up. In conclusion, the results of this prospective randomized study suggest that the addition of TMG to a triple immunosuppressive regimen (Tac, MMF, and steroids) did not modify the incidence of acute rejection episodes or long-term survival and was responsible for increased leukopenia rates.