This study examines the influence of peer norms on sharing of injection paraphernalia (e.g., indirect sharing behaviors, including sharing of cookers, cotton, rinse water and back/front loading) among Puerto Rican injection drug users (IDUs) in Bayamon, Puerto Rico, and East Harlem, New York City. Data were collected from 873 Puerto Rican IDUs recruited in the two locations by outreach workers. Multiple logistic regression was conducted using sociodemographic and other control variables (e.g., education, frequency of injection, pooling money to buy drugs, use of needle exchange program, injection in galleries and syringe sharing behaviors) and two types of norms related to sharing of injection paraphernalia--encouraging risk norms (what others approve) and objecting to risk norms (what others disapprove). One type of norms, encouraging or approval norms, was associated with indirect sharing in New York but not in Puerto Rico. Pooling money to buy drugs, use of shooting galleries and syringe sharing was associated with indirect sharing in both locations. Prevention programs to reduce indirect sharing behaviors should take into consideration different types of risk norms in order to reduce indirect sharing risk behaviors.