Two cohorts of alumni, leading-edge and trailing-edge baby boomers, first tested in their college years, were followed to ages 43 (N = 136) and 54 (N = 182) on a measure of Erikson's theory of psychosocial development. Hierarchical linear modeling was used to model the trajectory of growth for each psychosocial issue across middle adulthood. As predicted, the early psychosocial issues (trust, autonomy, and initiative) showed patterns of slow and steady increases in favorable resolution, as did the midlife issue of generativity. Industry, found in earlier investigations on the samples to change to differing degrees by cohort, continued to show cohort differences through midlife. The quadratic terms indicated that growth was curvilinear for both cohorts on identity and intimacy, and ego integrity showed variations by cohort, with the older cohort showing steeper patterns of increases. Gender differences were observed on intimacy, with women receiving higher initial scores, but the curves showed deceleration through midlife. Tests of variations in growth curves by the life history variables of educational attainment, occupational prestige, commitment to a long-term relationship, and parenthood status showed variations by cohort, but a general pattern of catching up emerged in which those who entered early adulthood at a relative disadvantage in terms of psychosocial development were able to attain favorable outcomes by midlife. (Contains 6 figures, 10 tables and 1 footnote.)