Objective: This study describes the effectiveness of 'Uma Tori', an STI/HIV-prevention intervention for women of Afro-Surinamese and Dutch Antillean descent in the Netherlands, aimed at increasing awareness of sexual risk and power in relationships and improving sexual decision-making skills. Methods: Intervention effects were evaluated in a pre-post-test design, using self-report questionnaires among a simple of 273 women. Data were analysed using intention-to-treat, MANOVA with repeated measures and Bonferroni correction for multiple comparisons. Additionally, a qualitative process evaluation, using logbooks and interviews, was conducted to assess fidelity and completeness of intervention implementation. Results: The results showed positive effects on participants' knowledge, risk perceptions, perceived norms and sexual assertiveness. In addition, after the programme, participants had stronger intentions to negotiate and practice safe sex. Furthermore participants communicated more with their partners about safe sex. Conclusion: The effects of 'Uma Tori' are promising and the intervention seems to support attempts to reduce sexual-risk behaviour among Afro-Caribbean women. Practice implication: The evaluation of the programme suggests that this interactive, multiple session, multi-faceted small-group intervention is successful in increasing participants' awareness. sexual assertiveness, intentions to negotiate safe sex, and communication about sexual behaviour with partners. This programme is applicable in practice, provided that it is gender specific and culturally appropriate.