This long-term study found that moral reasoning as conceptualised by Kohlberg(1 981 1985) can develop into adulthood. Predominant& white, well-educated, m W -c l a s s particz$ants were interviewed four times at 4-year intervals (N = 44). Stage deuelopment was sequential and continued throughout the lqe spanJ although its occurrence decreased with advancing age in a curvilinear fashion. Post-conventional reasoning was demonstrated by seven adults. Stage of moral reasoning correlated with age strong& in children and moderateb in adultsJ and was moderately correlated with education in all age groups, Addi~onaUyJ advance in moral reasoning stage was correlated with increase in education in adults. Although no systematic gender dzrerences were fmnd across age groupsJ men in the younger adult group had si&zzj?cantly higher scores than women.This paper reports results from a longitudinal and cross-sectional study of the development of moral reasoning across the life span [I]. Investigated were the sequence and trajectory of development, particula3y in adulthood, and the relationships between educationy gender, and moral reasoning stage change. Of particular interest was the investigation of Piagetian-type, structural moral reasoning development during adulthood and the impact of education on such development during that period.The conception of moral reasoning used here relies primarily on Kohlberg's smcrural-developmental model of mural reasoning and its development the stage descriptions, criteria and many assumptions of which have been thoroughly articu-