Background/Aims: Transfusion transmission is the only known transmission route of the recently identified GBV-C. To date, no evidence of household transmission of GBV-C has been reported. In the present study, a case of acute GBV-C hepatitis was investigated with respect to the mode of transmission. Methods: A 24-year-old woman with acute GBV-C hepatitis and her asymptomatic husband were examined. Two GBV-C RNA samples, isolated at different times from both the patient and her husband were amplified by reverse transcriptase-polymerase chain reaction using sequences from the NS3 region. Sequencing of this region was subsequently performed for all four samples. Results/Conclusions: The genomic RNA sequences of GBV-C isolated from each partner at two different time points were found to be 100% homologous. However, these genomic GBV-C RNA sequences differed in the NS3 (helicase) region from the genomic RNA isolated from the GBV-C prototype previously reported by Simons et al. Nonetheless, high homology (83%) was found between the GBV-C prototype and the GBV-C isolated from our patients. In addition, four nucleotides of the GBV-C RNA in the present study are unique and are not present in any other reported sequences of GBV-C. These results strongly suggest that GBV-C is one of the etiological agents involved in severe liver injury and was transmitted between this couple.