OBJECTIVES: This study explored the demographic characteristics of hepatitis C patients in the Kota Setar (KS) district, Kedah, Malaysia, the prevalence of intravenous drug use (IVDU) as a risk factor among these patients, and the associations between IVDU and demographic characteristics. METHODS: Retrospective data pertaining to 713 patients from January 2009 to December 2013 were retrieved from hospital and disease notification records for analysis. The risk factors for hepatitis C virus (HCV) infection were grouped into IVDU and non-IVDU risk factors for analysis using multiple logistic regression. RESULTS: Of the hepatitis C patients included in this study, the most common age group was 31 to 40 years (30.2%), and male patients (91.2%) made up the overwhelming majority. Ethnic Malays constituted approximately 80.4% of the patients, and IVDU was the main risk factor (77.8%) for HCV infection. Multiple logistic regression showed that male patients were 59 times more likely to have IVDU as a risk factor for HCV infection. Single patients were 2.5 times more likely to have IVDU as a risk factor. Patients aged ≥71 years were much less likely than patients aged ≤30 years to have IVDU as a risk factor for HCV infection. CONCLUSIONS: IVDU was found to be an important risk factor for HCV infection among patients in the KS district. The factors associated with IVDU included age, sex, and marital status. Appropriate preventive measures should be developed to target the groups in which IVDU is most likely to be a risk factor for HCV infection.