Background: There is a paucity of research concerning the identification of individual characteristics predictive of outcome in the treatment of personality disorders ( PDs). Methods: In this study, we carried out a predictor analysis of a sample of 73 hospitalized patients with a primary diagnosis of cluster B PD admitted to two different psychosocial programs for PD: ( a) long-term inpatient treatment, and ( b) a step-down program. Results: Younger age, higher Global Assessment Scale intake scores, longer length of treatment, absence of self-mutilation and avoidant PDs were a significant predictor of outcome at 24-month follow-up. Selfharming patients allocated to the step-down program had higher rates of improvement compared with patients allocated to the long-term inpatient model. Conclusions: The findings may carry potential clinical implications concerning patient selection and treatment delivery for inpatient and outpatient psychosocial programs for cluster B PD. Limitations include a relatively low sample size for a regression analysis, and a larger sample of cluster B patients may be needed to ensure greater reliability of results. Copyright (c) 2007 S. Karger AG, Basel.