Hepatitis C virus (HCV) infection is common among people with substance abuse histories and a burden for U.S. veterans in particular. This study compares self-reported HCV between 1,652 veterans and 48,013 nonveterans who received public-sector substance abuse treatment in Los Angeles between 2006 and 2010. A higher percentage of veterans than nonveterans reported HCV (6.5% vs. 3.8%, p < .0001). Homelessness and mental illness explained, respectively, 8.6% and 7.1% of the difference in HCV between the two groups, adjusting for other variables. Reducing homelessness and mental illness among veterans may also help reduce the excess burden of HCV in this population.