This study examined the relationship between anxiety disorders and suicidal ideation or suicide attempts in a nationally representative sample (N = 5877; age, 15-54; response rate, 82.4%). A modified version of the Composite International Diagnostic Interview was used to make DSM-III-R mental disorder diagnoses. Two multivariate logistic regression analyses were performed with suicidal ideation (N = 754) and suicide attempts (N = 259) as dependent variables. In each regression, the independent variables entered were lifetime social phobia, panic disorder, agoraphobia, generalized anxiety disorder, simple phobia, and posttraumatic stress disorder (PTSD). Covariates in the analyses were sociodemographics, lifetime mood disorders, substance use disorders, nonaffective psychosis, antisocial personality disorder, and presence of three or more lifetime DSM-III-R diagnoses. PTSD was significantly associated with suicidal ideation (adjusted odds ratio = 2.79; p < 0.01) and suicide attempts (adjusted odds ratio = 2.67; p < 0.01). None of the other anxiety disorders were significantly associated with suicidal ideation or attempts. The robust association between PTSD and suicide attempts has important implications for psychiatric assessment of suicidal behavior. Future research is required to investigate the mechanisms underlying the relationship between PTSD and suicidal behavior.