This article reports an evaluation of the Addressing Substance-Related Offending program in the English and Welsh Probation Service. Participants were 319 adult male offenders who had a history of substance use and were serving community sentences. A quasi-experimental design was used to compare the reconviction rates of offenders who completed the program, offenders who started but did not complete the program, and a comparison group of offenders who were not allocated to the program. Multivariate analysis showed that at one-year follow-up the completers had a significantly lower rate of reconviction and longer time to reconviction than the non-completers, and the non-completers had a significantly higher rate of reconviction and shorter time to reconviction than the comparison group. No differences were found in reconviction between the completers and comparison group.