The outcome of de novo hepatitis C virus (HCV) infection in heart transplant recipients of HCV-antibody positive organs is not known. The aim of the study was to determine the short-term outcome of de novo HCV infection in recipients of HCV-positive donor organs. HCV-antibody negative recipients of HCV-antibody positive hearts were identified from January 1, 1991 to February 28, 1998. Control patients matched for year of transplantation were also identified. Twenty-eight patients (22 males, mean age of 56 Ψ 11 SD) received hearts from HCV-antibody-positive donors. The control group was similar to the patients in all clinical and demographic aspects. Twenty-three patients had detectable viremia by reverse-transcription polymerase chain reaction (RT-PCR). Of these 23 patients with de novo HCV infection, 7 (30%) developed HCV-related liver disease. Three patients (13%) had chronic hepatitis and 4 patients (17%) developed severe acute cholestatic hepatitis (ACH). Mycophenolate mofetil (MMF) use (P β«Ψβ¬ .04) and high viral load at onset of acute liver disease (P β«Ψβ¬ .02) were associated with ACH. Overall survival was similar between patients with de novo HCV infection and controls (P β«Ψβ¬ .20). Development of ACH (P β«Ψβ¬ .02) and MMF use (P β«Ψβ¬ .0009) were associated with decreased survival in patients with de novo HCV infection. The present study showed that survival of patients with de novo HCV infection was similar to a matched control group. HCV-related severe ACH is associated with a poor short-term outcome in patients with de novo HCV infection. MMF use may be associated with a higher incidence of HCV-related severe ACH and a poor short-term outcome.