This study examined the relation between comorbid and pure (non-comorbid) anxiety disorders and both substance dependence and substance use problems in a community sample of 1747 young adults ages 18-23 years. Results indicate that collectively anxiety disorders, both pure and comorbid with other psychiatric diagnoses, are predictive of substance dependence. When temporal order was controlled, anxiety disorders generally preceded the onset of substance dependence. However in analyses in which PTSD was excluded, anxiety disorders were no longer predictive of substance dependence, suggesting that the increased risk associated with anxiety disorders is largely if not wholly attributable to PTSD. Finally, comorbid and pure anxiety disorders were found to be predictive of the number of alcohol and drug use problems.