Polarisation processes, which began in Croatia in the 1950's, resulted in disparate socio-economic development, in an uneven spatial distribution of the population, and in a concentration of people, jobs and housing in urban settlements. Coastal cities, as hubs and agents of socio-economic development, in their regions became focal points for the concentration of the population, while islands and hinterland areas suffered depopulation and demographic ageing. Intense in-migration had a positive influence on the demographic development of coastal cities. They became hotbeds of bioreproduction and up to the most recent intercensus period (1991–2001) displayed dynamic population growth. However political and economic changes in this recent period, together with the effects of the war, deepened and accelerated increasingly unfavourable demographic processes, which were reflected in an overall reduction of the population of coastal Adriatic cities, as well as in a deterioration of its structure. Decreasing fertility, demographic ageing and changes in life values brought about a transformation of the family, and hence changes in the size of households and in the relations among family members. The general trend today involves a gradual reduction in the number of household members, and a continuous increase in the number of two and one-member households.