This study aimed to develop and implement a customized training program related to the delivery of an integrated human immunodeficiency virus - sexually transmitted infections (HIV-STI) risk reduction intervention for peer-facilitators and to evaluate its immediate outcome including changes in trainee knowledge, attitudes, and self-reported competence and confidence. We developed and delivered a structured training program and materials about HIV and STI prevention in a university setting. The training was offered to candidate facilitators who were planned to be involved in a larger project, known as Integrated HIV-STI Risk Reduction Program. Ten candidate facilitators participated in the training program and completed both the pretest and posttest survey questionnaire. The data were analyzed using SPSS version 17.0 software package and Wilcoxon signed rank test was applied to assess the impact of the training program. Overall, the trainees' performance in HIV-related and STI knowledge, attitude and stigma scores had significantly increased compared to the baseline. The median scores for HIV and STI knowledge after the training significantly increased from 22.0 to 30.5 (p=0.007) and 8.0 to 9.5 (p=0.005), respectively, whereas the median score on the positive attitude towards HIV and STI prevention rose from 39.0 to 57.0 (p=0.011). Upon completion of the program, 80-100% of the trainees believed that they were competent and confident in performing most of the designed sexual health intervention activities. This preliminary study suggests that a customized on-site training program on sexual health intervention could significantly improve their knowledge, attitude and practice related to HIV-STI prevention.