ABSTRACT Aims To determine levels of health service utilization among heroin users, the types of prescription drugs obtained by heroin users and the contribution of benzodiazepine use in health service utilization and prescribed drug use. Design Cross-sectional survey. Setting Sydney, Australia. Participants A total of 615 current heroin users recruited for the Australian Treatment Outcome Study (ATOS). Findings Sixty per cent of subjects had consulted a general practitioner (GP) and 7% a specialist in the preceding month. An ambulance had attended 11% of subjects in the preceding month. Forty-eight per cent of subjects had prescriptions dispensed for medication in the preceding month. Thirty-nine per cent of participants had prescriptions dispensed for psychotropic medications, representing 80% of all prescriptions. Twenty per cent of subjects had prescriptions dispensed for non-psychotropic medications (20% of prescriptions). The most commonly prescribed drugs were benzodiazepines (59% of prescriptions), which had been obtained by 30% of subjects. Benzodiazepine users had more GP and psychiatrist visits, were more likely to have had an ambulance attendance and had significantly more dispensed prescriptions. Conclusions There were high levels of health utilization among heroin users. Prescription drug use was common, and dominated by psychotropic drugs. Benzodiazepine use was a dominant factor in the use of services and in prescriptions dispensed. Despite increased awareness of the harms associated with benzodiazepines, they continue to be prescribed widely to heroin users.