OBJECTIVES: Anxiety disorders are among the most common mental health conditions in the United States but study of their impact on labor productivity has been limited. The objective of this study was to estimate the annual indirect costs due to anxiety disorders in the U.S. population. METHODS: Retrospective analysis was conducted of the 1999 Medical Expenditure Panel Survey (MEPS). The MEPS provided data from a nationally representative sample of 24,618 respondents and their medical care and health insurance providers and employers. Data extracted for this study included medical conditions and employment information comprised of hourly earnings, hours worked per week, and disability days. Anxiety disorders were defined using the current Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) and were mapped to corresponding ICD-9-CM codes and included anxiety and panic disorders, stress disorders, obsessive compulsive disorder, and phobias. Patients with an anxiety disorder who incurred absence from work were identified using ICD-9-CM codes and variables denoting disability days. Indirect costs were calculated for patients who missed workdays using the human capital approach. Sample estimates were weighted and projected to the population and 95% confidence limits were calculated using the Taylor expansion method. RESULTS: As a percentage of the population, the number of patients with an anxiety disorder who missed workdays was low, at 0.20 percent (95% CL=0.13 to 0.27). However, the associated indirect costs were substantial, estimated at $2,981,633,568. Mean indirect costs were $5347 per patient who missed workdays. Relative to the entire population, mean indirect costs per person were $10.79. CONCLUSIONS: Although the prevalence of anxiety disorders resulting in absenteeism was found to be relatively low, the corresponding losses in productivity were almost $3 billion. This suggests long-term disability associated with these conditions and highlights the importance of early diagnosis and treatment to minimize work loss.