Purpose: Alcohol use reaches its peak during young adulthood. The current study examined transitions in drinking status across a one year period in Swedish and American young adults while also examining the association between country of origin, educational status, tobacco use, andmarijuana use on the probabilities of heavy drinking and transitions in heavy drinking over time. Methods: Young adults (N=3342; mean age=17.7 (SD=0.53; 56.6% female) were recruited from Sweden (n=2171) and US (n=1181) schools and assessed prospectively at 6- and 12-months following the baseline assessment. The Daily Drinking Questionnaire was used to assess changes in the quantity and frequency of alcohol use. Educational status, tobacco use, andmarijuana use were also assessed prospectively at 6- and 12-months. Results: Latent Markov models were used to examine changes in alcohol use from baseline to the 12-month follow-up, as well as cross-sectional and cross-lagged associations between heavy drinking and educational status, tobacco use, and marijuana use over time. The “low drinking class” had, on average,