Nosocomial spread of HCV and other blood-borne pathogens continues to occur in the Western world despite the screening of blood products. Using molecular and epidemiological methods we investigated an outbreak of HCV involving 3 patients following percutaneous coronary intervention at a Swedish hospital. The most likely mode of transmission was contamination of a multidose vial of saline used for the flushing of intravenous catheters. It may, therefore, be prudent to restrict the use of such vials, in addition to promoting vigorous adherence to standard hygiene procedures in order to prevent the recurrence of similar outbreaks in the future.