Previous research has shown that the association between education and health is partly mediated by working conditions. So far, most studies fail to take into account working careers and instead focus on working conditions at one point in time. This study examines the extent to which current and lifetime exposure to working conditions differ between educational groups, and whether taking into account lifetime exposure rather than current exposure improves our understanding of educational differences in health. A representative sample of the Dutch population (n = 1561) with retrospective information about working careers shows that lower educated men are significantly more exposed to adverse working conditions than higher educated men. These differences increase over the life course. Among women there are relatively small educational differences in exposure. Lifetime exposure to adverse working conditions explains a significant part (a third) of the health differences between the highest and lowest educated men. Moreover, measurements of lifetime exposure to working conditions offer a better explanation for educational differences in health than measurements of current exposure. Among women, only relative lifetime exposure to working conditions can explain a small part of the educational differences in health, while current and absolute lifetime exposure do not explain these differences.