BACKGROUND. HIV prevalence growth in Ukraine is conditioned primarily by the injection drug use. However, the rates of the sexual way of HIV transmission increased over the last three years. Behavioral surveys demonstrated that women who use drugs and are in long-term heterosexual relationships appear more vulnerable to HIV compared to males or single women. Therefore, the hypothesis for this study is that couples’ counseling can be effective in prevention HIV and Hepatitis C in drug using women.METHODS. Research consists of three parts that include bio-behavioral data collection on couples, intervention implementation, and six month follow-up. Research will be conducted in six cities randomized to intervention and comparison sites. Study participants (1000 couples) will be recruited in the study with the Respondent Driven Sampling method. Participants will be asked to provide information on their drug use and sexual practices and their relationship. Participants will be recruited into the intervention that will consist of three consecutive counseling sessions.RESULTS. Data collection will take place between May - July 2011. Of 10 sites selected for data collection, only six that demonstrated better recruitment will be chosen for further research participation and randomization. At each of the study sites, between 100 – 125 couples will be surveyed and tested. Study protocol was approved by the Ethics Committee. The study will have a number of limitations such as representativeness, high rate of loss to follow-up and challenges in recruitment and retention of study participants.CONCLUSIONS. This study will help to investigate the relationship between drug using women and men. Study findings will be used for better adjustment of HIV prevention programs to the needs of vulnerable populations.