OBJECTIVES: People addicted to opioids contribute a significant burden to society, both in terms of quality of life (QoL) and economic consequences.  Untreated users are more likely to be out of work, commit crimes and require healthcare resources.  Treating patients has been demonstrated to reduce these factors.  However, some users receiving formal care continue to misuse that treatment, leading to other significant consequences for society. This study evaluated the potential impact of a novel formulation (buprenorphine/naloxone; suboxone), aimed at mitigating misuse and diversion. Increasing the currently limited number of treatments available will likely increase the number of people in treatment. The objective was to assess cost-effectiveness of two approaches to managing opioid users, buprenorphine/naloxone and methadone, and, further, to compare the use of any treatment against no treatment. METHODS: A cost-effectiveness model was built, incorporating the costs and benefits associated with each treatment. Healthcare unit cost data were taken from published data and databases, including NHS Reference Costs 2009-2010 and PSSRU Unit Costs of Health and Social Care 2010. Crime costs were taken from Home Office publications. Crime and hospitalisation rates, by treatment, were taken from an observational study of 109 patients in Scotland. Health related QoL figures, by treatment, were taken from an SF-36 questionnaire study. RESULTS: Over 6 months, it was estimated that savings associated with reduced crime (buprenorphine/naloxone versus methadone) were £2129, and savings from reduced health care visits were £1409.  Based on a combination of mortality and QoL improvements, patients on buprenorphine/naloxone were shown to gain 0.087 QALYs compared to those receiving methadone. CONCLUSIONS: The model showed that the cost implications of crime, hospitalisation and misuse and diversion were key drivers of the results. Use of buprenorphine/naloxone resulted in a saving of £3538 due to reduced crime and hospitalisations, whilst providing a benefit to QoL.