Since the great recession, fertility has been declining steeply in some high-income countries. It is, however, unknown whether the ideal number of children, a key predictor of fertility behaviour, has also declined, either in parallel or prior to fertility decline. Finland is known for its supportive family policies, but is among those countries, which have experienced drastic and poorly understood fertility decline over the last decade. Using repeated cross-sectional survey data from the Finnish Family Barometers, we examined birth cohort changes in ideal number of children among men and women born in 1970–94. Our findings indicate that the ideal number of children was lower among more recent compared to earlier birth cohorts. This difference in fertility ideals was driven by larger proportions of those preferring to remain childless among the recent birth cohorts. This suggests that attitudes of Finns towards childbearing have changed and may contribute to recent fertility decline.