The effectiveness of the Reasoning and Rehabilitation (R and R) program with juvenile offenders in an English prison was evaluated using reconviction and reimprisonment at eighteen months post-release as outcomes. A group of offenders who completed the program (n = 31) were compared with a group of offenders who did not receive the program (n = 31). The comparison group was created by retrospectively matching offenders by offence type, sentence length, age, and number of previous convictions. A small reduction in reconviction during the first eighteen months after release was found for the treatment group, although the difference was not significant. A slightly larger reduction in reimprisonment for the treatment group was found, but again the difference was not statistically significant. No significant differences were observed between the survival curves for the two groups. These findings contrast with more positive outcomes reported by large-scale studies of the R and R program with adult males in the UK and Canada. Possible explanations for these findings are discussed. (Contains 4 tables and 1 figure.)