The latest edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) proposes a novel hybrid system of personality disorder diagnosis in addition to the one previously laid down in the DSM-IV-TR. This alternative diagnostic system, published within Section III of the DSM-5, was hoped to overcome the inherent limitations of categorical diagnosis by integrating the categorical and dimensional approaches to personality disorders. As such, it constitutes a bridge between psychiatric pathology classifications and findings from psychological research on the structure of normal personality. At the core of the hybrid DSM-5 system lies a new model of pathological personality traits, operationalized using the Personality Inventory for DSM-5 (PID-5). This paper outlines the background and main features of the DSM-5 hybrid system of personality disorder diagnosis with a focus on the dimensional model of pathological traits and definitions thereof. The current status, application potential and limitations of the DSM-5 diagnostic system and the pathological traits model are also discussed. In another paper, the authors present the PID-5 inventory and report on a study investigating a Polish adaptation of this instrument.