Hepatitis C virus (HCV) is transmitted primarily through direct percutaneous exposure to infected blood. Sporadic HCV cases exist and may represent more than 10% of HCV transmission. We report the first case of documented transmission of HCV during a fight from a person who unknowingly had chronic HCV infection to a person who subsequently contracted acute hepatitis C. Patient-to-patient transmission was ascertained by sequence analysis of part of the NS5B genome and phylogenetic analysis. This case report suggests that sporadic HCV infection may be a result of blood exposure. This example of transmission could have a major impact in sports such as boxing or rugby. We suggest that in any fight, single use or nondisposable material should be used to dry blood to avoid such contamination.