Much-needed research on Thai adolescents (age 15-19), the fastest growing group of AIDS victims in Thailand, this study differentiates risk behavior among classes, unlike most AIDS research in Thai society, and focuses on how gender and economic factors among adolescents influence their risk-behavior patterns leading to the contraction of HIV/AIDS. Using ethnographic methods focusing on class and gender, I identified several risk-taking behaviors. Each class in Thai society tends to be at-risk from a different level of sexual relationships and drug use. The lower class seems to be the most at risk because of having many sexual partners, having unprotected sex, and sharing needles while, those in the middle class use only personal screening for their sexual partners and also sharing needles. Although the higher class is less at risk compared with other classes, a few do visit prostitutes and consume drugs. Class is also correlated to the level of knowledge and education about AIDS. Although each received the same health education provided through the same source and same health text, adolescents in each class catch the message differently. My research data showed that adolescents of the higher class showed a more complete knowledge about AIDS. There are also many patterns of HIV/AIDS risk-taking behaviors that correlate to cultural gender differences. Although all classes appear to adhere to the ideal norm of virginity being the best sexual-practice, in reality, this only applies to members of the upper class. The middle and, especially, the lower classes do not apply this norm to themselves at all: They practice premarital sex, even though they may verbalize the ideal norm. Other studies have focused on gender relations according to this ideal Thai norm; however, this ideology does not match the reality. In conclusion, with the lack of research in this area, Thai adolescents are being placed at greater risk. Thus, I make recommendations for further research and prevention methods. For example, health education should be more up-to-date and explain to adolescents the connection between sexual relationships and AIDS rather than focusing primarily on the reproductive process. Further, parents, schools, and teenagers themselves can visit with health professionals at the hospitals and anonymous clinics to learn more about STDs, especially, HIV/AIDS. If put into practice, these recommendations will positively reduce the spread of AIDS in Thailand. / Graduation date: 1999