Between 1992 and 1996, the authors interviewed a group of street-recruited injection drug users who reported syringe sharing at the first interview. The users were given HIV testing and counseling semi-annually. At a six-month follow-up interview, 60% reported quitting syringe sharing. Statistical analysis showed that high-risk drug users and those who continued to use the syringe exchange program were more likely to quit sharing syringes compared with non-syringe exchange users. The authors conclude that initiation and continuation of syringe exchange program use among high-risk drug users is independently associated with cessation of syringe sharing. Syringe exchange program use can be an important component in reducing the spread of blood-borne diseases among high-risk injection drug users.