SUMMARY The total fertility of women born in 1940 goes from 2.0 to 2.4 children per woman in the various countries under study. No significant difference is to be noticed in that respect between Eastern and Western Europe. Total fertility throughout the fifty previous cohorts was quite different in these various countries. In most of the Eastern countries, it fell C()nlinuouslv; in Czechoslovakia it remained stable for 20 to 30 cohorts; in Western Europe it rose up again. These differences are connected with the fertility level which rose up again only in those countries which it had fallen below 2 children per woman. On the contrary, reproductive behaviour, year by year, does not show much change. Its variations stem from the changes in th...