In this paper we question the validity of factitious disorder as a meaningful psychiatric diagnosis. When the diagnosis is used there is often the assumption that the person engaging in the 'deception' is not lying in the traditional sense of being deliberately misleading. Moreover, little is known about the aetiology or psychopathology underlying factitious disorder, and the legitimacy of deception as a mental disorder has been questioned. It is argued that while illness deception may be more common that hitherto assumed, factitious disorder as a distinct type of psychiatric disorder is conceptually flawed, diagnostically impractical and clinically unhelpful and should be dropped from existing nosologies.