Bolivia has a high STI rate and an accelerating HIV/AIDS rate. The majority of the country's newly diagnosed HIV/AIDS cases come from the province of Santa Cruz in eastern Bolivia, where this study took place. In this study, the investigator assessed the notion that Bolivian truck drivers are a bridge population of HIV transmission within heterosexual networks. This investigation determined risks of HIV/STI transmission through interviews, surveys, and workshops given to the truck drivers. Special attention was given to self reports of sexual behavior, cognitions and ego maturation stages, in order to assess risk. Mixed methodology was the research paradigm of choice, utilizing qualitative and quantitative phases. Workshops were designed, implemented, and evaluated. Analysis was completed on survey results from 246 male truckers (aged 18 to 67). More than half (56%) of these truckers admitted to having sex with casual partners. In addition, from 30% (quantitative inquiry) to 52% (qualitative inquiry) of these truck drivers have had sexually transmitted infections. Three factors predicted condom use: Age, Outcome expectancies, and Perceived social norms. Only one factor predicted STI history: Number of sex partners. Adult stage theory did not directly impact sexual behavior. A high risk of HIV/STI transmission has been detected in Bolivian truck drivers. This notion supports other studies involving truck drivers, and calls attention to the need for tailored health education programs for this population. Furthermore, younger truck drivers are at greater risk of HIV transmission than older truck drivers, in spite of their increased condom use. Sexual health workshops for Bolivian truck drivers are worthwhile and can be most effective when co-managed with truck companies or unions. Counseling, testing, and follow up research programs can best be implemented through these already-existing management structures. Future programs need to emphasize other behaviors besides condom use. Workshops should also include truckers2 spouses as participants. Lastly, since casual sex partners of truck drivers rarely fit the mold of a commercial sex worker, effort should be made to describe these casual partners and design subsequent workshops for them.