Cirrhotic patients with hereditary hemochromatosis (HHC) have an increased risk of primary liver cancer (PLC). The purpose of this study was to determine the prevalence of primary liver cancer in patients with HHC undergoing orthotopic liver transplantation (OLT). Five liver transplant centers were surveyed; clinical and pathological data on 37 patients with HHC undergoing OLT were retrospectively collected and analyzed. The diagnosis of HHC was established by a combination of serum transferrin-iron saturation, hepatic iron index (HII), and/or pattern of liver iron staining. The diagnosis of HHC had been unsuspected before OLT in 13 of 37 (35%). Primary liver cancer was found in the explants of 10 of 37 patients (27%) and was unsuspected in 7 of 10 (70%); 8 were hepatocellular carcinoma, and 2 were cholangiocarcinoma; foci of hepatocyte dysplasia were found in 6 additional patients. Mean (+/- SEM) hepatic iron content and HII in 20 patients without prior phlebotomy or bleeding were 17.2 mg/g dry weight (+/- 2.9) and 5.5 (+/- 0.8), respectively. The overall 1-year survival rate after OLT in the 37 HHC patients was 58% (v 55% for HHC patients with PLC). We draw the following conclusions: (1) the diagnosis of HHC is often unsuspected before OLT, and HHC should be evaluated pretransplantation by direct and indirect markers; (2) HHC patients undergoing OLT have a high prevalence of primary liver cancer, the majority being unsuspected; and (3) HHC patients have poorer than average survival after OLT, which cannot be explained solely by the presence of concomitant PLC.