Injection drug users have high rates of hospital use, however, the specific contribution of injection-related infections to hospitalization has never been determined. After reviewing 92 consecutive admissions of HIV-negative injection drug users to Rhode Island Hospital in 1998, we found that 49% were related to infections and an additional 24% were due to the biological effects of the injected drug. Admissions that were for injection-related infections were significantly more costly than other admissions of injection drug users ($13958 vs. $7906). We conclude that considerable savings may result from preventative care of this population, including instruction in skin-cleaning techniques.