Background: This study examined associations between anxiety and work-related outcomes in an anxiety disorders clinic population, examining both pretreatment links and the impact of anxiety change over 12 weeks of treatment on work outcomes. Four validated instruments were used to also allow examination of their psychometric properties, with the goal of improving measurement Of work-related quality of life in this population. Methods: Newly enrolled adult patients seeking treatment in a university-based anxiety clinic were administered four work performance measures: Work Limitations Questionnaire (WLQ), Work Productivity and Activity Impairment Questionnaire (WPAI), Endicott Work Productivity Scale (EWPS), and Functional Status Questionnaire Work Performance Scale (WPS). Anxiety severity was determined using the Beck Anxiety Inventory (BAI). The Clinical Global Impressions, Global Improvement Scale (CGI-I) was completed by patients to evaluate symptom change at a 12-week follow-up. Two severity groups (minimal/mild vs. moderate/severe, based on baseline BAI score) were compared to each other on work measures. Results: Eighty-one patients provided complete baseline data. Anxiety severity groups did not differ in job type, time on job, job satisfaction, or job choice. Patients with greater anxiety generally showed lower work performance on all instruments. job advancement was impaired for the moderate/severe group. The multi-item, performance scales demonstrated better validity and internal consistency. The WLQ and the WPAI detected change with symptom improvement. Conclusion: Level of work performance was generally associated with severity of anxiety. Of the instruments tested, the WLQ and the WPAI questionnaire demonstrated acceptable validity and internal reliability. Depression and Anxiety 26:1165-1171, 2009. (C) 2009 Wiley-Liss, Inc.