Theories of adult development all agree that adulthood is a time of important changes in goals, resources, and coping. Yet, impressed with the rank-order stability of individual differences in personality, many researchers interested in personality traits and personality assessment doubt that personality changes in meaningful and systematic ways during adulthood. This article reviews large studies of mean-level change in personality characteristics measured with broad-band personality inventories, and includes both cross-sectional and cross-cohort longitudinal research. The results show considerable generalizability across samples, cohorts, and studies. In particular, people score higher with age on characteristics such as conscientiousness, agreeableness, and norm-adherence, and they score lower with age on social vitality. These findings provide evidence that personality does change during adulthood and that these changes are non-negligible in size, systematic, not necessarily linear, and theoretically important. (C) 2002 Elsevier Science (USA). All rights reserved.