The prevalence of soft tissue infections (abscesses, cellulitides, infected ulcers) among injection drug users (IDUs) is estimated to be between 21% and 32%. Little is known regarding the health care utilization associated with these infections. This study describes IDUs seeking emergency department (ED) care for soft tissue infections, their inpatient health care utilization, including operating room procedures, and the types and locations of infections associated with increased inpatient health care utilization. This study used a medical record case series of all IDUs seeking initial care for soft tissue infections at an urban, public emergency department from November 1999 through April 2000. Initial care for IDU-related soft tissue infections was sought by 242 patients. Most were male (63.6%), Caucasian (69.4%) and without health insurance (52.0%), and most had abscesses (72.3%). All patients with only cellulitis had arm or leg infections, while most abscesses were arm, deltoid, or buttock infections (81.1%). Forty percent of the patients were hospitalized, and 44.3% of the hospitalizations were for 3 or more days. Patients with only cellulitis were more likely to be hospitalized compared to those with abscesses. Among those with abscesses, deltoid abscesses were 5.2 times more likely to receive an operating room procedure compared to other abscess locations. IDUs with cellulitis and deltoid abscesses commonly required inpatient care and operating room procedures. The morbidity associated with such infections and the intensive use of hospital services needed to treat these infections provide strong rationale for the development of preventive interventions and improved care for this neglected clinical problem.