There is a well-established need to conduct careful assessments of sex offenders being considered for treatment. Research indicates that sex offenders are a diverse group and that differences in their characteristics will have important implications for the development of individualized treatment programs. Facilities for conducting assessments of sexual arousal are essential for identifying those offenders who have deviant sexual preferences and require special treatment that targets the deviant preferences. Research also suggests that institutionally-based programs which offer little in the way of followup may produce only short-term treatment gains. The effective treatment of sex offenders must incorporate followup contact or "booster treatments if long-term benefits are to be achieved. One of the most encouraging signs of the newer, more comprehensive programs for sex offenders is that treatment strategies have taken into account a broad range of factors that research has identified as potentially relevant to the control of sex offenders' deviant behavior.