<p>This article reviews the prevalence and treatment of comorbid conditions (personality disorders) in individuals with learning disabilities. It is based on a new clinical services model under the direction of the author at a secure hospital facility. The overarching framework of the programme is drawn from cognitive behaviour therapy, interpersonal theory and developments in attachment theory. The author describes the work of a forensic learning disability personality disorder service that has been specially created to diagnose patients and to improve the standards of care and treatment they receive. Personality disorders can be reliably diagnosed in individuals with learning disabilities, yet comparatively little is known about the interaction between personality disorders and learning disabilities, and most importantly of all, how to best treat these coexisting conditions.</p>