Background: Premature termination is a common problem in the treatment of personality disorder. Efforts to improve compliance should begin by recognising risk factors for premature termination. This prospective study identified predictors of premature termination from a day treatment program for personality disorder. Methods: Consecutively admitted patients with a personality disorder (n = 197) were assessed with self-report and interview measures. Patient personality characteristics were the primary predictors. Others were demographic, initial disturbance, and personality disorder variables. Cox proportional hazards regression was used. Results: Risk of terminating prematurely significantly increased if the patient had been previously hospitalised for psychiatric difficulties, was younger, had fewer prior contacts with health and social services, and had more severe borderline personality disorder traits. Conclusions: Information about which patients are at high risk for premature termination can help clinicians take measures to modify the risk. This might involve selection decisions, pre-treatment preparation, close monitoring during treatment, or addition of adjunctive interventions.