There are six HIV prevention programs for homeless youth whose efficacy has been or is currently being evaluated: STRIVE, the Community Reinforcement Approach, Strengths-Based Case Management, Ecologically-Based Family Therapy, Street Smart, and AESOP (street outreach access to resources). Programs vary in their underlying framework and theoretical models for understanding homelessness. All programs presume that the youths' families lack the ability to support their adolescent child. Some programs deemphasize family involvement while others focus on rebuilding connections among family members. The programs either normalize current family conflicts or, alternatively, provide education about the importance of parental monitoring. All programs aim to reduce HIV-related sexual and drug use acts. A coping skills approach is common across programs: Problem-solving skills are specifically addressed in four of the six programs; alternatively, parents in other programs are encouraged to contingently reward their children. Each program also engineers ongoing social support for the families and the youth, either by providing access to needed resources or by substituting a new, supportive relationship for the existing family caretaker. All of the interventions provide access to health and mental health services as basic program resources. A comparison of HIV prevention programs for homeless youth identifies the robust components of each and suggests which programs providers may choose to replicate. (Published Abstract) 53 references