HCV infected patients frequently ask their physician about the risk of transmission to their partners. Although it is easy to answer that the risk does exist, it is difficult to quantify. We studied the transmission of HCV infection in stable heterosexual couples: anti-HCV positive patients in hemodialytic therapy and their partners. Thirty-four couples were tested by third generation ELISA and RIBA. Blood samples of anti-HCV positive patients were evaluated by RT-PCR and detected sequences were genotyped by restriction fragment length polymorphism. Concordance of infection was observed in only one couple in which both subjects were in dialytic therapy. One other partner had two positive ELISA tests and an indeterminate RIBA, with negative RT-PCR, which may suggest a false positive or a previous resolved infection. Either sexual relations, sharing of personal items and history of parenteral exposure (hemodialysis, blood transfusion) could explain transmission in the only couple with concordant infection. We observed, in accordance with previous reports, that this risk is minimal or negligible in stable heterosexual couples.