Describes modifications to the facet scales of the Neuroticism, Extraversion, and Openness Personality Inventory (NEO-PI) and the development of new scales to measure facets of Agreeableness and Conscientiousness. Conceptual distinctions within these domains were suggested by a review of the literature, and pilot studies provided preliminary evidence for the validity of new facet scales. Item analyses among 1,539 21-64 yr old men and women were used to finalize item selection and to confirm the structure of the Revised NEO-PI (NEO-PIR) at both the item and scale level. Correlations of the NEO-PIR with other self-report scales (e.g., the Myers-Briggs Type Indicator) administered to 394 men and women provided evidence on convergent and discriminant validity.