We examined the prevalence of drug use related infectious complications among opioid using or dependent individuals and service charges associated with medical care received over a 2-year period at a public hospital. A computerized medical record review was used to identify 3147 individuals with diagnoses related to opioid use or dependence. Forty-nine percent of these patients were treated for bacterial infections and 30% presented for treatment of medical problems arising from the effects of the drugs themselves (e.g. drug withdrawal, overdoses, and drug-induced psychiatric symptoms). Mean charges were $13393 for these patients, nearly 2.5 times the average per patient charges for non-opioid using patients during the study period. Patients with diagnoses related to opioid use or dependence comprised 2% of the total patient population for this period, yet accounted for 5% of total charges. Homeless patients were less likely to have used ambulatory services and were more likely than non-homeless patients to have used emergency and inpatient services. Early detection of patients with opioid use or dependence problems, coupled with effective strategies to engage them in ambulatory preventive services, could allow interventions to reduce morbidity and associated charges in this patient population. The findings suggest that health care providers and policy makers consider policies that promote ambulatory care use among opioid users seeking medical care through the public health care system.