Buprenorphine/naloxone has recently been introduced in Australia and is available for unsupervised dosing within Queensland. A retrospective observational study of data collected during 2000-2007 for clients obtaining injecting equipment from the Brisbane Harm Reduction Centre in Queensland is presented. The numbers of service occasions and needles and syringes were used as surrogate drug use measures. Buprenorphine and naloxone were misused at lower rates when compared with buprenorphine and methadone. Furthermore, the misuse of opioid replacement therapies represented less than 5% of all illicit opioid injections. Implications and study limitations are discussed.