The prevalence of antibodies to hepatitis C virus (anti-HCV) in a population of intravenous drug users in Jeddah, Saudi Arabia was 74.6%. The anti-HCV prevalence in drug dependent patients who did not use the intravenous route was 10.5%. The anti-HCV prevalence in healthy Saudi males and in healthy non-Saudi's was 1.7% and 3.2% respectively. There is a need for public education to control the spread of the virus.