Acute graft rejection remains a major problem among additional sequelae in liver transplant recipients. Basiliximab, a chimeric monoclonal antibody with high affinity for the CD25 chain of the interleukin-2 receptor, has significantly reduced the incidence of acute rejection episodes in renal transplant recipients. This single-arm, open-label, multicenter study investigated the efficacy and tolerability of basiliximab immunoprophylaxis in adult patients undergoing first elective liver transplantation. One hundred one patients (70 hepatitis C virus [HCV]-negative patients, 31 HCV-positive patients) were administered basiliximab, 20 mg, by intravenous bolus injection the day of transplantation (day 0) and day 4. In addition, all patients were administered triple immunosuppressive therapy with cyclosporine, steroids, and azathioprine. The efficacy of basiliximab was assessed by conventional parameters, and tolerability was assessed by the incidence of adverse events, infections, and laboratory test result abnormalities. At 6 months, the incidence of first acute biopsy-confirmed rejection episodes was 22.8%. Rejections were more frequent in the HCV-positive (29.0%) than HCV-negative subgroup (20.0%; P ؍ .441). No rejection episode was graded histologically as severe, and no patient required antibody therapy for the management of acute rejection. Ten patients (9.9%) required treatment with tacrolimus for acute rejection episodes. Patient and graft survival rates at 12 months were 90.1% and 88.1%, respectively. Basiliximab caused no injection-site reactions, anaphylaxis, or cytokine release syndrome. Five malignancies were reported at 12 months: of these, three malignancies predated transplantation surgery. Compared with earlier studies, the addition of basiliximab immunoprophylaxis to triple immunosuppressive therapy provides increased efficacy in reducing the incidence of acute rejection episodes, with no clinically significant increase in adverse events. (Liver Transpl 2002;8: 123-131.)