During 2002--2009, rates of newly diagnosed hepatitis C virus (HCV) infection increased from 65 to 113 cases per 100,000 population among persons aged 15--24 years in Massachusetts. Accordingly, the Massachusetts Department of Public Health (MDPH) and CDC interviewed persons aged 18--24 years with HCV infection reported to MDPH during July 1--December 31, 2010, to elicit detailed information regarding demographic, clinical, and risk characteristics.