The article examines the process of transformation of the family institution in Belarus. Over a hundred years, the Belarusian family has undergone radical changes. As many specialists point out, there has been a transition from a patriarchal (traditional) multi-generational large family to an egalitarian, nuclear, small family. A comparison of the results of the 2009 and 2019 censuses reveals the main current challenges for the family institution: an increase in the number of singles, a decrease in the number of families, a decline in the number of married couples with underage children, and a reduction in the average family size. Positive trends include an increase in the number of children in households with underage children and an increase in the proportion of households with three or more children. One of the main challenges to demographic security is the reluctance to have children. According to census data, women's plans to have children have been assessed. Differentiation in birth planning across the country's districts has been identified. Based on the available demographic data and the results of the 2019 census, a typology of administrative districts of Belarus by the family structure and reproductive potential has been developed. The typology is based on the principles of rating and the main priorities of demographic security of the Republic of Belarus. Most districts in the Republic of Belarus are characterised by an average level of family structure and reproductive potential. The largest concentration of districts with a transitional type with above-average family structure and reproductive potential indicators is located in Brest, Gomel and Minsk regions