Aims: Residential rehabilitation (RR) is relatively expensive and is received by a minority of drug users seeking treatment. It is perceived to be particularly effective, but those entering RR may be more amenable to treatment than those treated in other modalities. The objective of this study was to explore ways in which opiate users treated in a residential setting differ, at treatment entry, from those treated in a community setting. Methods: Opiate users (N=406) who received either RR or community substitute prescribing (CSP) were sampled from the UK Drug Treatment Outcomes Research Study (DTORS). A logistic regression analysis, controlling for Drug Action Team, was used to predict the occurrence of RR versus CSP for the treatment of opiate dependence. Measures included self-reported levels of drug use, offending, social measures and health. Findings: RR clients were different to CSP clients in a number of respects that may positively influence treatment outcome; most importantly, their reasons for seeking treatment were different and they were better motivated. Conclusions: Higher treatment motivation may be one factor that explains why RR is a more effective treatment for clients with complex drug-related problems. © 2014 Informa UK Ltd. All rights reserved: reproduction in whole or part not permitted.