Since its approval as an immunosuppressive agent in renal transplantation, sirolimus (RAPA) recently has been used in the primary immunosuppression regimen at several liver transplant centers. One of the major side effects of RAPA is hypercholesterolemia, which is reported in up to 44% of patients. We describe our experience in 57 primary liver transplant recipients treated with RAPA and either cyclosporine A (CSA) or tacrolimus (TAC). We report the incidence and severity of hypercholesterolemia using a prednisone-free immunosuppressive regimen. Between January 2000 and September 2000, a total of 57 patients underwent transplantation at the University of Colorado Health Sciences Center (Denver, CO) with RAPA and either CSA or TAC. The initial 10 patients who underwent transplantation under this protocol were not administered corticosteroids, and the subsequent 47 patients were administered only 3 doses of methylprednisolone days 0, 1, and 2 postoperatively (1, 0.5, and 0.5 g, respectively). Total fasting cholesterol, high-density cholesterol, low-density cholesterol, and triglyceride levels were measured at monthly intervals. Mean serum cholesterol level was significantly greater in CSA patients (200 mg/dL) compared with TAC patients (158 mg/dL; P =.0003). Serum triglyceride levels were more than 2-fold greater with CSA (292 mg/dL) compared with TAC (134 mg/dL; P =.002). Hypercholesterolemia (cholesterol > 240 mg/dL) was present in 10 of 57 patients (18%) and was significantly more common in CSA-treated patients (8 of 27 patients; 30%) compared with TAC-treated patients (2 of 30 patients; 6%; P <.05). Hypertriglyceridemia (serum triglyceride > 300 mg/dL) was present in 10 of 57 patients (18%) and was significantly more common in CSA-treated patients (9 of 27 patients; 33%) compared with TAC-treated patients (1 of 30 patients; 3%; P <.05). We conclude that (1) concomitant use of TAC with RAPA reduces the prevalence and severity of posttransplantation dyslipidemia, and (2) these findings have important implications in the prevention of complications of hypercholesterolemia in liver transplant recipients.