OBJECTIVES: The purpose of this study is to: 1) characterize the changes in utilization of psychotropic medications among adults with anxiety disorder over a 6-year period (2004-2009), and 2) identify factors associated with psychotropic medication use. METHODS: Patients with anxiety disorder were identified in the 2004 to 2009 Medical Expenditure Panel Survey (MEPS). Psychotropic medication use was ascertained from a self-reported prescription file. The number and percentage of patients with anxiety using a psychotropic medication was calculated for each year and drug class. We used t-tests to compare psychotropic medication use between 2004 and 2009, and a logistic regression model to identify the factors associated with psychotropic medication use. RESULTS: The estimated number of adult patients who reported having an anxiety disorder increased from 18.9 million in 2004 to 21.4 million in 2009. The percentage of patients who reported ever using a psychotropic medication grew from 62.5% in 2004 to 68.6% in 2009 (p<0.05) and over one-third of patients reported ever using a selective serotonin reuptake inhibitors (SSRI) (35.3% in 2004 to 37.1% in 2009).  From 2004 to 2009, there was a significant increase in the use of benzodiazepines (26.1% to 32.9%, p<0.01), serotonin-norepinephrine reuptake inhibitors (SNRI) (6.5% - 10.5%, p<0.01), and atypical antipsychotics (4.8% to 8.4%, p<0.01). A higher prevalence and significant increase in the use of benzodiazepines was observed among older adults aged ≥ 65 years (43.9% in 2004 - 53.0% in 2009, p<0.01). Multivariate logistic regression results showed that white race, female gender, higher education, private insurance, and comorbid mood disorders were associated with self-reported psychotropic medication use. CONCLUSIONS: In the US, psychotropic medication use among patients with anxiety increased from 2004 to 2009. The high prevalence and increasing trend of benzodiazepine use among older patients with anxiety disorder needs more research to evaluate its implications.