The proposed study aims to address health disparities between Hispanic and non-Hispanic whites, particularly as it relates to HIV and drug use in Hispanic adolescents. This goal will be accomplished by two aims: AIM I is to develop an Internet-based version of the face-to-face Familias Unidas intervention (hereafter referred to as Internet-Based Familias Unidas); and AIM II is to evaluate the efficacy of Internet-Based Familias Unidas, relative to both face-to-face Familias Unidas and a community practice control condition, in preventing unprotected sexual behavior and drug use in a community sample of Hispanic adolescents living in Miami-Dade County. 270 Hispanic adolescents recruited from three high schools will be randomized using an urn design to one of three conditions: Internet-Based Familias Unidas, face-to-face Familias Unidas or Community Practice. Face-to-face Familias Unidas, a Hispanic-specific, family- centered intervention, has been found efficacious, relative to control conditions, in preventing adolescent unprotected sexual behavior and drug use in two randomized clinical trials (Pantin et al., 2009; Prado et al., 2007). Hierarchical Linear Modeling (HLM) will be used to test: (H1) Internet-Based Familias Unidas and face-to-face Familias Unidas will be more efficacious than Community Practice Control in preventing adolescent unprotected sexual behavior over time; (H2) Internet-Based Familias Unidas and face-to-face Familias Unidas will be more efficacious than Community Practice Control in preventing adolescent drug use over time; (H3) Internet-Based Familias Unidas will be more efficacious than face-to-face Familias Unidas in preventing adolescent unprotected sexual behavior over time; and (H4) Internet-Based Familias Unidas will be more efficacious than face-to-face Familias Unidas in preventing adolescent drug use over time. Additionally HLM will be used to determine whether (H1a) the effect of Internet-Based Familias Unidas and face-to-face Familias Unidas on adolescent unprotected sexual behavior will be partially mediated by family functioning; (H2a) the effect of Internet-Based Familias Unidas and face-to- face Familias Unidas on adolescent drug use will be partially mediated by family functioning; (H3a) the effect of Internet-Based Familias Unidas on unprotected sexual behavior will be partially mediated by participation rates; and (H4a) the effect of Internet-Based Familias Unidas on adolescent drug use will be partially mediated by participation rates. PUBLIC HEALTH RELEVANCE: The objective of the proposed study is to prevent and reduce HIV risk behaviors among Hispanic adolescents. The knowledge expected to be gained from this study will aid in the development of efficacious Internet-based preventive interventions to reduce HIV, unprotected sexual behavior, and drug use in Hispanic adolescents.