This article describes the results of several analyses of structure underlying the personality variables of the Jackson Personality Inventory (JPI; Jackson, 1976, 1994). Ten different data sets showed that, when three of the JPI scales were removed from the analyses, a very clear five-factor structure emerged. The five factors more or less resembled the well-known Big Five dimensions of personality. Somewhat at variance with the Big Five structure, however, was the tendency of our Conscientiousness factor to split into dependability and organization components. Furthermore, not all JPI variables found a place in the Big Five factor space. Risk Taking, Energy Level, and Value Orthodoxy were sufficiently independent of the obtained factors to suggest that those variables might define separate factors in their own domains. (C) 1996 Academic Press, Inc.