CASASTART (Striving Together to Achieve Rewarding Tomorrows, formerly known as Children at Risk), is a community-based, school-centered substance abuse and violence prevention program developed by the National Center on Addiction and Substance Abuse at Columbia University (CASA). CASASTART targets youths between 8 and 13 years old who have a minimum of four identified risk factors. Youth participants may remain in the program up to 2 years. Specific program objectives of CASASTART include reducing drug and alcohol use, reducing involvement in drug trafficking, decreasing associations with delinquent peers, improving school performance, and reducing violent offenses. CASASTART’s intervention model is informed by the research literature on social learning theory, social strain theory, social control theory, and positive youth development. Its eight fundamental components are community-enhanced policing, intensive case management, juvenile justice intervention, family services, after-school and summer activities, education services, mentoring, and the use of incentives to encourage youth development activities. Each site brings together key stakeholders in schools, law enforcement agencies, and social services and health agencies to develop tailored approaches to the delivery of the core service components consistent with local culture and practice. At all sites, CASASTART is staffed by case managers and requires the cooperation of area police departments and local social service and juvenile crime agencies.