Background: Social anxiety disorder (SAD) is highly comorbid with alcohol use disorders (AUD) yet the nature of this comorbidity remains unclear. To better understand these associations, we first examined whether SAD was related to AUD above and beyond relevant covariates. Second, we examined the psychosocial impairment associated with the comorbidity of SAD and AUD versus SAD without AUD. Third, the temporal sequencing of SAD and AUD among comorbid individuals was examined. Methods: Participants included 5,877 (50% females) adults from the National Comorbidity Survey. Results: As predicted, SAD was related to alcohol dependence (not abuse) after controlling for relevant conditions, indicating that SAD is linked to more severe alcohol impairment and that this link is not better accounted for by other pathology. Results also supported the hypothesis that the addition of alcohol dependence to SAD resulted in greater impairment across a variety of domains relative to SAD without alcohol dependence (e.g., greater rates of health care utilization, other psychiatric diagnoses, health problems, and greater interpersonal stress). Additionally, for the majority of comorbid individuals, SAD onset predated alcohol dependence onset, suggesting SAD increases vulnerability for misusing alcohol. Conclusions: Together, these data lend support for the contention that SAD may serve as a risk for alcohol dependence and indicate that the co-occurrence of these two conditions may result in greater personal and public health care costs. Depression and Anxiety, 2008. Published 2008 Wiley-Liss, Inc.