Blood-borne pathogens such as human immunodeficiency virus (HIV) and hepatitis C virus (HCV) are transmitted most commonly among injection drug users (IDUs) through the sharing of needles and syringes. Distributive syringe sharing (DSS) (i.e., passing on a used needle/syringe to another IDU) poses the potential risk of transmitting HIV and viral hepatitis to others. We studied the prevalence and correlates of DSS among IDUs enrolled in a randomized behavioral intervention trial designed to reduce behaviors associated with HIV and HCV transmission in five U.S. cities. Among 3129 IDUs ages 15-30 years who completed the baseline visit, 1432 (45.8%) engaged in DSS during the 3 months prior to baseline. Significant correlates of DSS were perception that peer norms condone needle sharing, frequent injection, not obtaining most syringes from needle exchange programs or pharmacies, injecting most frequently in shooting galleries and with sex partners, low perceived risk of HIV from sharing syringes, increased anxiety, low self-esteem, and having unprotected sex. Restricting to only those IDUs who reported not injecting with previously used syringes, similar independent correlates of DSS were found. These findings suggest that interventions to reduce ongoing transmission of blood-borne infections should focus on altering peer norms among networks of young IDUs.