We apply latent transition analysis (LTA) to characterize transitions over time in substance use behavior profiles among first-year college students. Advantages of modeling substance use behavior as a categorical latent variable are demonstrated. Alcohol use (any drinking and binge drinking), cigarette use, and marijuana use were assessed in a sample (N=718) of college students during the fall and spring semesters. Four profiles of 14-day substance use behavior were identified: (1) Non-Users; (2) Cigarette Smokers; (3) Binge Drinkers; and (4) Bingers with Marijuana Use. The most prevalent behavior profile at both times was the Non-Users (with over half of the students having this profile), followed by Binge Drinkers and Bingers with Marijuana Use. Cigarette Smokers were the least prevalent behavior profile. Gender, race/ethnicity, early onset of alcohol use, grades in high school, membership in the honors program, and friendship goals were all significant predictors of substance use behavior profile.