Trends in intergenerational economic mobility in Finland are analyzed using panel data from 1950 through 1999 on more than 250,000 sons and daughters born between 1930 and 1970. A significant decline is estimated in the intergenerational transmission elasticity from the 1930 birth cohort until the baby boom cohorts of the early 1950s. After that we observed no increase in the extent of mobility for 1950s and 1960s birth cohorts, but rather the reverse. The result holds both for sons and daughters. A decomposition of the intergenerational transmission elasticities across cohorts shows that most of the early decline in transmission reflected a drop in the influence of parental income on the children's earnings that operated through investments in the child's schooling. This early pattern is postulated to reflect the phases of secondary educational expansion at the time. Throughout, a rise is estimated in the intergenerational transmission elasticity with age at which sons and daughters are observed. This has also been noted in prior U.S. studies and, at least in this Finnish context, this seems to result almost entirely from rising estimated returns to education with age.