Objective: The efficacy of short-term psychotherapy has become an area of increasing interest. The primary objective of this study was to assess the results of two forms of short-term psychotherapy in patients with personality disorders. Method: Eighty-one patients with personality disorders were randomly assigned to brief adaptive psychotherapy, short-term dynamic psychotherapy, or a waiting list for therapy. Outcome at termination of therapy for the treatment groups and at the end of the waiting period for the waiting list group was evaluated by means of ratings of target complaints and scores on the SCL-90 and the Social Adjustment Scale. In addition, for 38 of the treated patients, target complaints were reevaluated an average of 1.5 years after treatment ended. Results: Patients in the two therapy conditions improved significantly on all measures in comparison with the patients on the waiting list. There was no significant difference between the results in the two therapy conditions. The waiting list period averaged approximately 15 weeks; treatment averaged 40 weeks. At follow-up, after an average of 1.5 years, target complaint ratings were not significantly different from those at the termination of therapy. Conclusions: These data indicate that brief adaptive psychotherapy and short-term dynamic psychotherapy are effective for patients with certain types of personality disorder and that the two therapy approaches do not differ in overall outcome.