Measures of temperament and early environment were obtained from 108 patients with major depression using the Tridimensional Personality Questionnaire (TPQ) and Parental Bonding Instrument (PBI). TPQ and PBI measures distinguished between depressed patients and controls. Depressed patients with comorbid axis I disorders appear to be temperamentally different from those who do not have these disorders. Those with alcoholism have higher novelty seeking (NS) scores; those with panic disorder have higher harm avoidance (HA) scores; and those with simple phobia have higher persistence (P) scores. More than half the patients had an axis II disorder. Those with a comorbid personality disorder recall worse parental care and have lower reward dependence (RD) scores. Individual personality disorders and DSM-III-R personality disorder clusters reflect to a significant degree underlying temperament as measured by the TPQ. These results suggest that it is possible to better understand the patterns of comorbidity between major depression, other axis I disorders, and personality disorders by studying the underlying temperament dimensions in these patients.