MLMC provides many programs and services that train service providers about CSE, to assist survivors of CSE, and to prevent youth from becoming exploited. MLMC offers CSE prevention groups (secondary prevention) and one-on=one survivor mentoring (tertiary prevention). In 2003, MLMC designed the prevention group curriculum with survivors, and has since trained 624 facilitators from 33 U.S. states and Canada to provide these prevention groups. Group facilitators - who often include clinicians, counselors, child welfare workers, or adult CSE survivors who have been free from CSE for at least 5 years - are trained in the 10-session curriculum in a 2-day training session. Starting in 2004, MLMC has offered one-on-one survivor mentoring to Eastern Massachusetts youth who are exploited or are at high-risk for CSE exploitation. The current report focuses on the methodology and findings of an evaluation of both the MLMC prevention group program and the survivor mentorship program, using a longitudinal, mixed-methods design. The evaluation sought to determine whether participation in this programming reduced CSE, dating abuse, non-voluntary police contact, and risk behaviors. It also qualitatively explored participants' experiences with MLMC and conducted a cost analysis of the MLMC prevention groups and survivor mentoring. This report presents preliminary results, because an in-depth data analysis is in progress. Preliminary results indicate that after adjusting for potential confounders, participants changed in positive directions for many of the outcome measures. Participating youth were three times less likely to report having been commercially sexually exploited in the past 6 months. 1 figure and 24 references