Personality psychologists from a variety of theoretical perspectives have recently concluded that personality traits can be summarized in terms of a 5-factor model. This article describes the NEO Personality Inventory (NEO-PI), a measure of these 5 factors and some of the traits that define them, and its use in clinical practice. Recent studies suggest that NEO-PI scales are reliable and valid in clinical samples as in normal samples. The use of self-report personality measures in clinical samples is discussed, and data from 117 "normal" adult men and women are presented to show links between the NEO-PI scales and psychopathology as measured by D. N. Jackson's (1989) Basic Personality Inventory and L. Morey's (1991) Personality Assessment Inventory. The authors argue that the NEO-PI may be useful to clinicians in understanding the patient, formulating a diagnosis, establishing rapport, developing insight, anticipating the course of therapy, and selecting the optimal form of treatment for the patient.