The management of needs and risks in personality disordered offender populations has become a focus for health and criminal justice services in the UK. Recent studies demonstrate the effectiveness of schema focussed therapy (SFT) for patients with borderline personality disorder. This study was an exploratory trial of the feasibility of implementing SFT in a population of patients with personality disorder in a high secure hospital in England. Preliminary evaluations of the effects of SFT were conducted to investigate whether those receiving SFT demonstrated significant improvements on measures of anger, impulsiveness, schemata and interpersonal style. No significant effects were evident although there was a significant increase in defectiveness/shame schema in the SFT group. Lack of effectiveness of SFT is likely due to the preliminary nature of this study. Future trials of SFT need to ensure comprehensive therapist preparation, control of TAU, bigger samples, address attrition and provide more intensive therapy.