The working of the educational system in a welfare state was examined in a longitudinal study of a cohort (initially 1,029) of students followed from age 7 to age 23 years. An initial sample included 329 males and 342 females, of whom 352 had working class careers and 319 had middle class careers. Relationships among social origin, gender, and career were analyzed; school performance, differentiation, and careers were determined for a final sample of 655 young adults. Social background had a heavy impact on career. Two-thirds of the working class children remained in a working class career, and two-thirds of the middle class children stayed in the middle class. Working class children were more likely to remain in the same career position, with less shifts of class position, than were middle class children. Class position shifts were also more common among women than men. In primary schools, differences in cognitive performance among students increased and students followed different career paths. Student perspectives on schooling in retrospect indicated more school acceptance among middle class students and among those with middle class careers. The results highlight the need to view the impact of the educational system in terms of cultural responses and social mobility in the welfare state. Three tables and two diagrams present study data. A 53-item list of references is included. (SLD)