OBJECTIVE: The purpose of this study was to assess the duration of periods of euthymia in patients with dysthymia. METHOD: All patients with dysthymia who came to the Center for Anxiety and Depression over a 10-month period (N=22) were interviewed by the author regarding the duration of their euthymic episodes. RESULTS: The 22 patients with dysthymia reported euthymic periods from 2 to 30 days (mean=8.0 days, SD=6.6). CONCLUSIONS: The euthymic period of up to 2 months that is specified in DSM-IV for dysthymic disorder might confound the results of clinical trials. Data from additional groups of dysthymic patients would be useful when considering this issue for DSM-V.