The Life Functioning Questionnaire (LFQ) is a 5-min, 14-item, gender-neutral self-report questionnaire designed to assess role function over the preceding month in four domains: workplace, duties at home, leisure time with family and leisure time with friends. To validate the LFQ for use as an instrument assessing functional outcome in patients with a mood disorder, the LFQ was administered to three different samples of patients (N=87). Fifty-nine concurrently completed the self-report version of the Social Adjustment Scale (SAS-SR) and 32 concurrently had a Clinical Global Impression Scale for Bipolar Disorder (CGI-BP) assessment. The LFQ proved to have high internal consistency reliability, high test-retest reliability, excellent concurrent validity with the SAS-SR, and high validity as a measurement of severity of illness when compared with the CGI-BP. The LFQ provides a reliable, consistent and valid assessment of function at work and home in both male and female patients with a mood disorder.