The purpose of this survey was to determine current practices of cardiothoracic transplant centers regarding transplantation of hearts and lungs into hepatitis C (HCV)-seropositive candidates and the use of organs from HCV-seropositive donors. A telephone survey of 48 cardiothoracic transplant centers was conducted in October 1992. Questions included the center’s policy for listing HCV-seropositive candidates; if, and under what conditions, organs from HCV-seropositive donors would be used; and which HCV assays were used. Forty-five programs responded; 75% will list an HCV-seropositive candidate, either directly or by lack of routine screening to exclude such patients; only 16% will not accept HCV-seropositive candidates; 9% had no policy. Overall, 69% will accept organs from HCV-seropositive donors, at least for selected recipients (22% for any recipient, 45% for HCV-seropositive and/or status I recipients; 2% do not screen donors). A total of 27% will never accept organs from an HCV-seropositive donor, and 4% had no policy. Thirty centers provided information on HCV methodology. All but one use a second generation ELISA or EIA as a first-line test. A positive result will be followed by a confirmatory assay/liver biopsy in 42%. The variation in practices reflects the ambiguity in the literature. Adequate evaluation of morbidity and mortality due to HCV infection in this population has not yet been possible, although currently available reports do not show a substantial increase. Prospective controlled trials in cardiothoracic transplant patients are necessary.