This study tested several clinical hypotheses about personality traits of migraine and tension headache patients in a controlled design. Achievement motivation was found to be elevated in both headache groups. The tension headache patients also exhibited greater rigidity in comparison to the migraine group and the controls. In migraine patients, both traits were positively correlated with duration of headache attacks. When the two patient groups were combined, the headache patients had, in addition to raised achievement motivation and rigidity, more fear of failure and less impulsiveness than the controls. No evidence was found for higher prevalence of neuroticism and obsessive-compulsive behavior in the headache groups. Neither migraine nor tension headache patients revealed an abnormal pattern of defense mechanisms. Generally, those traits related to aspects of performance were found to be more prevalent in headache patients than in controls.