This paper examines the scientific, practical, and ethical issues surrounding the employment of the Random Controlled Trial (RCT) in the evaluation of sexual offender treatment. Consideration of these issues leads us to conclude that the RCT design is not suitable for determining the effectiveness of sexual offender treatment. We also examine the RCT study by Marques et al. (Sexual Abuse: A Journal of Research and Treatment and Evaluation 17:79-107, 2005) that is often held up as the model for the evaluation of sexual offender treatment. We found several problems with this study that, in our opinion, reduce its relevance for deciding whether treatment is effective with these clients. Finally, we examine two alternative strategies for evaluating treatment that may allow treatment providers to more readily examine, and report, the results of their programs.