This study examined the effectiveness of an adapted 4-session HIV prevention program. Participants included 490 adolescents who participated in either the 8- or the adapted 4-session HIVEd program. Analyses to identify mean changes in HIV-related knowledge, attitudes, self-efficacy, and behavioral intentions between participants in either the 4- (n = 274) or 8-session (n = 216) programs were completed. Findings indicate participants in both programs had positive changes at post interview across all study outcomes. No significant differences in changes between participants in the 4- and 8-session programs were found except that male adolescents in the 4-session program had significantly higher mean changes in condom knowledge (p < .01). The adaptation of the 8-session HIVEd program was undertaken to better reach and accommodate the needs of a high risk incarcerated adolescent population. Findings demonstrate that HIV prevention interventions for high risk populations may be successfully adapted and condensed when based on rigorously evaluated and theoretically driven programs.