 Suicide attempts are not only associated with increased likelihood of eventual death by suicide Lonnqvist Ostano, 1991, increased risk of repeat suicidal behavior Goldston et al., 1999; Leon et al., 1989, and risk of physical injury, but suicidality is also one of the primary reasons for psychiatric emergencies and psychiatric hospitalizations Peterson et al., 1996. Suicide attempters, particularly repeat attempters, often have histories of both depression and substance abuse problems. Cognitive behavioral interventions have been shown to have promise in the treatment of depression Brent et al., 1997, suicidality Henriques, Beck, Brown, 2002, and substance use disorders in youths Dennis et al., in press; Kaminer et al., 2002. Relapse prevention approaches have been shown to have utility with substance abusing adults Witkiewitz Marlatt, 2004, and conceptually are well suited for the prevention of both suicidal behavior and substance use among young people. The purpose of the research outlined in this application is therefore to develop, refine, and test a cognitive behavioral relapse prevention intervention CBT-RP for dually diagnosed suicidal adolescents and young adults. 