The aims of the study were: (1) to study possible associations between temperament, personality dimensions, and psychopathological variables in a clinical sample of euthymic patients with bipolar disorder (BD) and cyclothymia; and (2) to assess how Cloninger's temperament and personality dimensions were associated with affective temperaments. Participants, consisting of 60 patients with BD (type I or II) and cyclothymia in the euthymic phase, completed Akiskal's Temperament Evaluation of Memphis, Pisa, Paris, and San Diego-Autoquestionnaire (TEMPS-A), and Cloninger's Temperament and Character Inventory-revised version (TCI-R). The diagnostic groups differed in past hospitalization, for age at onset of the disorder, and on two affective temperaments: the TEMPS-A Hyperthymia, and the TEMPS-A Irritability. There were six significant associations between affective temperaments and Cloninger's personality dimensions, ranging from 0.26 to 0.54. The measures of Akiskal and of Cloninger tap common behavioral features in patients with bipolar disorder and cyclothymia, yet the differences indicate that the two measures are not redundant. BD and cyclothymic patients differed significantly in temperament and personality, differences that may have important implications for treatment.