We compared the utility of several trait models for describing personality disorder in a heterogeneous clinical sample (N = 94). Participants completed the Schedule for Nonadaptive and Adaptive Personality (SNAP, Clark, 1993b), a self-report measure that assesses traits relevant to personality disorder, and two measures of the Five Factor Model: the Revised NEO Personality Inventory (NEO-PI-R; Costa and McCrae, 1992) and the Big Five Inventory (BFI; John, Donahue, & Kentle, 1991). Regression analyses indicated substantial overlap between the SNAP scales and the NEO-PI-R facets. In addition, use of the NEO-PI-R facets afforded substantial improvement over the Five Factor Model domains in predicting interview-based ratings of DSM-IV personality disorder (American Psychiatric Association, 1994), such that the NEO facets and the SNAP scales demonstrated roughly equivalent levels of predictive power. Results support assessment of the full range of NEO-PI-R facets over the Five Factor Model domains for both research and clinical use.