Akiskal and Mallya (Psychopharmacol Bull. 1987;23:68-73) proposed criteria defining 4 affective temperaments-hyperthymic, irritable, cyclothymic, and dysthymic. This study aims to develop and validate, using a 3-point rating scale, a short questionnaire that assesses these temperaments.The Affective Temperament Questionnaire (ATQ) was administered to a family-based sample of individuals with major depressive disorder (MDD), bipolar disorder (BP), or no mood disorder (N = 378). Factor analyses, internal consistency, and analysis of variance were undertaken to examine the factorial structure and concurrent validity (relative to Axis I mood disorder diagnosis) of the ATQ. Affective Temperament Questionnaire data were evaluated with respect to raw scores and dominant affective temperament.Three factors emerged--hyperthymia, cyclothymia, and dysthymia--which had moderate to high internal consistency. Support for the concurrent validity of ATQ was found, whereby temperament scores and rates of dominant affective temperaments differed with respect to mood disorder diagnosis. Hyperthymia and cyclothymia were more prevalent among individuals with BP than among individuals with MDD or no history of a mood disorder. Dysthymia occurred at a relatively similar rate among individuals with MDD or BP.Our findings support the use of the ATQ for collecting information regarding affective temperaments and for furthering understanding regarding the links between affective temperament and mood disorders.