Cytomegalovirus (CMV) disease is the most common infection following liver transplantation, occurring in approximately 20% of recipients. In liver transplant recipients, CMV is associated with a higher cost following transplantation, subsequent infections, and recurrent hepatitis C. Since we have initiated a prednisone-free immunosuppressive regimen in January 2000, we have noted an extremely low incidence of CMV disease in our cohort of liver transplant recipients. We report our findings here. All 150 patients transplanted between January 2000 and December 2002 with tacrolimus (or cyclosporin A) and sirolimus, and 3-day corticosteroid taper were retrospectively analyzed. Recipients who were CMV IgG negative with a CMV IgG-positive donor ("CMV mismatch") received conventional prophylactic therapy with intravenous and oral ganciclovir. The incidence of CMV disease (defined as positive tissue culture or positive immunohistochemical stain of affected tissue or CMV-DNA >3000 associated with clinical symptoms) was recorded for each patient. The proportion of "CMV mismatches" (donor CMV IgG positive, recipient CMV IgG negative) was 15%. The mean total number of days of ganciclovir prophylaxis (intravenous and/or oral) administered to "CMV mismatch" patients was 45.6 days. The incidence of CMV disease in patients receiving sirolimus primary immunosuppression was 2%. The mean time to diagnosis of CMV disease was 139 days. (1) The incidence of CMV disease is very low using a prednisone-free, sirolimus immunosuppressive regimen. (2) Two possible explanations for this finding include appropriate prophylaxis with ganciclovir and low levels of immunosuppression including the absence of prednisone.