To investigate the effects of marital status and position on DSM-III-R personality traits, we administered the self-rating questionnaires of the Structured Clinical Interview for DSM-III-R Personality Disorders to 757 male computer engineers, aged 20 to 49 years, at a computer manufacturing plant. The scores for six of eleven personality traits were significantly higher in single computer engineers than in married ones. Also, among the engineers aged 40 to 49, the scores for six personality traits of section-heads were significantly higher than those among persons in the other positions. These findings suggest that "maladaptive" personality traits, defined by the DSM-III-R, differ with marital status and position in a company.