Ninety-three patients with panic disorder and mild or no agoraphobia were treated for their panic disorder by using either 11 sessions of individual cognitive-behavior therapy or imipramine. Before and after treatment, their panic disorder symptomatology was assessed, and a self-report measure was administered to measure personality disorder characteristics [Klein et al., 1990: Wisconsin Personality Disorders Inventory]. In addition, some patients received this personality assessment again after six monthly maintenance sessions. Both treatments were equally effective in reducing panic disorder symptomatology, and both treatments had a positive influence on personality disorder characteristics. Personality disorder characteristics did not predict treatment outcome in either group. The implications of the findings for the assessment of personality and the treatment of panic disorder are discussed.