Research on the dimensions of personality represented in the English language has repeatedly led to the identification of five factors (Norman, 1963). An alternative classification of personality traits, based on analyses of standardized questionnaires, is provided by the NEO (Neuroticism, Extraversion, Openness) model (Costa & McCrae, 1980b). In this study we examined the correspondence between these two systems in order to evaluate their comprehensiveness as models of personality. A sample of 498 men and women, participants in a longitudinal study of aging, completed an instrument containing 80 adjective pairs, which included 40 pairs proposed by Goldberg to measure the five dimensions. Neuroticism and extraversion factors from these items showed substantial correlations with corresponding NEO Inventory scales; however, analyses that included psychometric measures of intelligence suggested that the fifth factor in the Norman structure should be reconceptualized as openness to experience. Convergent correlations above .50 with spouse ratings on the NEO Inventory that were made three years earlier confirmed these relations across time, instrument, and source of data. We discuss the relations among culture, conscientiousness, openness, and intelligence, and we conclude that mental ability is a separate factor, though related to openness to experience.