The Sex Offender Treatment and Evaluation Project (SOTEP) is a controlled, longitudinal study of the effectiveness of an intensive cognitive-behavioral treatment program for rapists and child molesters. In the first part of this chapter, we describe the treatment program and how we are evaluating it and summarize some of our preliminary findings. In the second part, we propose, based on our experience in SOTEP, a number of recommendations about the design, implementation, and evaluation of sex offender treatment programs.