In response to the commercial sexual exploitation of children (CSEC) within five U.S. cities, the CSEC Community Intervention Project (CCIP) was created to enhance collaboration among nongovernmental organization (NGO) representatives, law enforcement officials and prosecutors in Chicago, Atlantic City, Denver, Washington, D.C., and San Diego. A total of 211 participants were surveyed during a 3-day CCIP training institute held in each city. Evaluation data suggest that participants were positively influenced in their knowledge, skills, and attitudes regarding CSEC. Our findings inform NGO representatives, law enforcement officials, and prosecutors of the importance of professional training and the benefits of cross-disciplinary collaboration in addressing CSEC. (Contains 8 tables.)