OBJECTIVE: We aimed to evaluate the convergent validity and responsiveness of the work functioning impairment scale (WFun) in patients with depression, a major disease causing presenteeism. METHODS: Baseline testing was performed using WFun, the Quick Inventory of Depressive Symptomatology (QIDS), 17-item Hamilton Depression Rating Scale (HAM-D), and Montgomery-Asberg Depression Rating Scale (MADRS) in 37 outpatients with major depression or bipolar disorder who were working. The QIDS and WFun scores were measured several times for responsiveness evaluation. RESULTS: Regression analyses showed significant positive correlations between baseline WFun and HAM-D and MADRS scores. Changes in WFun and QIDS scores were positively correlated for QIDS scores. CONCLUSIONS: Our results suggest that WFun is convergently valid and responsive for determining the clinical severity of depression in workers treated as psychiatric outpatients.