Alcohol use increased steadily across time; expectancies also had significantly, although smaller, increasing slope. Significant interrelationships were found between the development of alcohol use and positive expectancies. More importantly, greater increases in expectancies were significantly related to greater increases in alcohol use. By placing these results in the context of other research, support for the utilization of these aspects of Social Cognitive Theory (SCT) with American-Indian adolescents and young adults were found. An estimated half of all new HIV cases in the United States occur to persons under 25. Given this rate, HIV prevention efforts focus on adolescents and young adults. In addition, the HIV epidemic has been increasing over the last decade for American-Indians. Also, alcohol use and misuse have been associated with a number of HIV risk factors, such as multiple sex partners, inconsistent condom use, and a history of STD diagnosis. American-Indian youth are considered high risk for alcohol misuse at early ages. This study incorporated two lines of research. First, indicating an important role for alcohol use in understanding HIV risk. Second, suggesting the importance of reciprocal determinism in the development of positive expectancies and alcohol use. The study examined ways in which patterns of the development not only of alcohol use but also of positive alcohol outcome expectancies for ages 14-24 were related to HIV risk and protection. It also examined the differential development of alcohol use and outcome expectancies by categories of lifetime and current HIV risk at young adulthood. Tables, figure, references