Noninjecting heroin users (NIHU) that were 16-30 years old were street recruited in Chicago between 2002 and 2005 to examine factors associated with having ever injected. Participants completed computerized self-administered interviews and provided specimens for HIV and hepatitis serotesting. Of 689 NIHU, 51.2% were non-Hispanic Black, 64.4% were male, and the median age was 25 years. Former injection was reported by 17.9%; of those, 66.7% injected <10 times. Multivariable analysis identified individual and social factors that place young NIHU at increased risk of injection. Targeted interventions are necessary to prevent transitions to injection and reduce transmission of HIV and viral hepatitis infections. The study's limitations are noted.