Background and aims: High drug related mortality amongst former prisoners in the 4 weeks following release is an internationally recognised problem. Naltrexone injections at release could diminish this by blockading opioid receptors, but naltrexone is not licensed for injection for treating opiate misuse in the United Kingdom and some other countries. This study examined the likelihood of accepting a naltrexone injection at release, and the relationship of this likelihood to other relevant variables. Method: Sixty-one male prisoners with a history of heroin use, who were approaching release from two prisons in the north-west of England, provided likelihood ratings for accepting a naltrexone injection if it were to have been available. Additional data was gathered regarding demographic and drug use histories, and also from psychometric instruments relevant to drug misuse and treatment preparedness. Results: Maximum likelihood ratings for accepting a naltrexone injection were recorded by 55.7% of the sample with only 9.8% indicating no likelihood of accepting an injection. Likelihood ratings were positively related to serving a current sentence for an acquisitive offence compared to drug related or violence offences, and negatively related to peak methadone dosages during the current sentence. Conclusions: Although naltrexone injections were not available to participants in this study, the findings suggest that the potential uptake for this intervention is sufficient to warrant a clinical trial with this population of British prisoners, with a view to potential changes to its current licencing status. However, the importance of individual patient readiness for such an abstinence orientated intervention is emphasised by the negative correlation between the likelihood ratings and recent methadone doses.