A multivariate analysis of dimensions of problem drinking and their stability across time is conducted through a series of confirmatory factor analyses (as opposed to exploratory factor analyses used in previous studies), using self-report data from a longitudinal sample of adolescents and youth. Analyses are performed separately by age and gender. Results indicate that traditional measures of problem drinking represent at least two distinct dimensions--intensity of use and use-related problems--rather than a unitary construct for adolescent males and females. The results also suggest that dimensions of problem drinking remain relatively stable from 15 to 21 years of age, except that alcohol-related problems are unstable for males from 15 to 18 years of age.