ABSTRACT Both the California Psychological Inventory (CPI; Gough, 1987) and the five-factor model of personality have roots in folk concepts of personality. The present article offers a conceptual analysis of CPI scales in terms of the five-factor model. In the first study, judges rated the item content of CPI scales in terms of the five factors. In the second, CPI scales were correlated with the factors as measured by the NEO Personality Inventory (NEO-PI; Costa & McCrae, 1985b) in a sample of 348 men and women ages 19 to 92. Both studies showed meaningful links between CPI scales and four of the factors; Agreeableness appeared to be underrepresented in CPI scales. The utility of systematic rational item analysis in terms of the five factors and the evolving relation of folk concepts to psychological constructs are discussed.