Identity formation is an important developmental task of the college years. Previous research has demonstrated that identity commitment, as defined by James Marcia, is related to decreased substance use and problems. That is, individuals who are identity achieved or foreclosed use substances less frequently and experience fewer substance-related problems than do individuals who are classified in the statuses of identity diffused or moratorium. However, Marcia discussed identity as developing in two domains, the occupational and the ideological (religious beliefs and political ideology). To date, no studies have examined in which domain commitment is associated with a decrease in substance use and problems. Using a sample of 283 college students, the present study sought to examine the relationship between identity development in these domains and alcohol use and problems. It was hypothesized that identity commitment in the ideological domain, rather than the occupational domain, would account for the relationship between overall identity commitment and substance use and problems and that this relationship would be mediated by anxiety. Overall, the hypotheses were not supported by the data. Identity commitment was not a significant predictor of alcohol use and problems and identity crisis was a better predictor than commitment. Religious identity appeared to the best predictor of alcohol use and problems of the three identity domains. Of the separate identity statuses, identity achievement had the highest predictive value for alcohol use. Finally, there was no evidence in the data to support the hypothesis that any relationships between identity and alcohol variables were mediated by anxiety. Limitations of the current study include differences in sample and measures as compared to other studies, as well as a number of variables that were not measured here. Implications and applications for working with adolescents and for substance abuse treatment are discussed along with recommendations for future studies.