Background: Depression is a risk factor for incident myocardial infarction (MI), but little is known about the independent or additive risk from anxiety disorders. Methods: In a 7-year retrospective cohort design, we identified a cohort free of cardiovascular disease in fiscal years 1999 and 2000 that contained 96,612 patients between 25 and 80 years of age who had an International Classification of Diseases, Ninth Revision, Clinical Modification code indicating a diagnosis of depression in 2000 (baseline) and 259,387 patients without depression. Cox proportional hazards models stratified by depression were computed to test for a main effect of anxiety disorder unspecified, generalized anxiety disorder, panic disorder, social phobia, obsessive-compulsive disorder, and posttraumatic stress disorder (PTSD) on risk of incident MI. The models were adjusted for multiple MI risk factors and sociodemographics. Results: Depressed as compared to nondepressed Veterans Administration patients were at increased risk for incident MI (HR 1.39; 95% CI 1.34-1.45). In nondepressed patients those with anxiety disorder unspecified (HR 1.34; 95% CI 1.21-1.47), panic disorder (HR 1.43; 95% CI 1.11-1.83), and PTSD (HR 1.25; 95% CI 1.16-1.36) were at increased risk for incident MI. The independent risk associated with anxiety disorders was reduced in patients comorbid for depression. Conclusions: In Veterans Administration patients free of heart disease in 1999 and 2000, those with depression, anxiety disorder unspecified, panic disorder, and PTSD were at increased risk of incident MI. Anxiety disorders are independent risk factors for MI. Depression partially accounts for the effect of anxiety disorders on risk of MI in patients with both conditions.