Data were obtained from the Voices of Indian Teens project, a longitudinal school-based survey that examined the use of alcohol and other substances as well as the potential risk and protective factors for such use among AI high school students. The primary sample came from seven predominantly AI high schools in four communities west of the Mississippi. Data for the analyses were collected semiannually (every 5 to 7 months) from the fall of 1993 through the spring of 1996. The survey asked respondents about the use of alcohol, marijuana, inhalants, cocaine, and other drugs. Youths were classified according to their stage of substance use at each wave in which they participated. The progression of substance use was identified by following the longitudinal course of each adolescent's responses to the substance-use questions. The study found that individuals who initiated their substance use with marijuana and/or inhalants were at greater risk for progressing to stage 2 substance use. The hazard curves show an initial increase in risk of substance-use progression with a subsequent peak and decrease in risk. The hazard of progression varied across the four communities studied, confirming findings that the risk of substance-use progression varies across AI communities. Gender was not found to be a marker for substance-use progression. The risk of progression from stage 1 to stage 2 increased with the age of transition to stage 1, contrary to other studies of non-AI youths. Finally, a powerful seasonal association with substance-use progression emerged, consistent with other studies; substance-use progression was more likely to be reported in the spring than in the fall over the bulk of the school year. Clinical, policy, and research implications are discussed. 1 table, 5 figures, and 44 references