||The Czech Republic is between countries with the lowest level of fertility. Demographic changes connected with low fertility have negative impact mainly on current social system. Remedies of these changes is usually refer to pronatalist policy, which involves the intention of maintaining a favourable development of fertility or, in the case of a negative situation, it wants to achieve its reversal. The essay focuses on efficiency of pronatalist policy in Czech's countries, during 20.century. Next issue of this essay is if the cost of popation policy would not be higher than cost of modification of social system.