Research has suggested that social-class differences in adult health may be at least partly determined by conditions earlier in life. In 2636 Finnish men, we assessed impact of childhood and adult socioeconomic conditions on adult mortality risk by examining whether differing socioeconomic life-courses from early childhood to adulthood were associated with different risks of all-cause and cardiovascular mortality. Compared with high-income adults, those with low income had increased relative risks of all-cause (2.54, 95% CI 1.83-3.53) and cardiovascular (2.37, 1.51-3.7) mortality, but these increased risks were not related in either adult group to childhood socioeconomic conditions. Men who went from low-income childhood to high-income adulthood had the same mortality risks as those whose socioeconomic circumstances were good in both childhood and adulthood (1.14, 0.56-2.31, all causes; 0.99, 0.39-2.51, cardiovascular). By contrast, men who experienced poor socioeconomic circumstances as both children and adults were about twice as likely to die as those whose position improved (2.39, 1.28-4.44, all causes; 2.02, 0.9-4.54, cardiovascular). Our findings suggest that socioeconomic conditions in childhood are not important determinants of adult health. We caution against this interpretation--a life-course approach to socioeconomic differences in adult health requires understanding of the social and economic context in which individual life-courses are determined.