The provisional results of the 1991 census of population indicate a continuation of trends established in relation to fertility and migration in the early 1980s (Cawley, 1990) which have resulted in a halting of the growth in population that commenced in the early 1960s. It is estimated that the total population declined by approximately 17,200 (0.5%) since 1986 giving an estimated total of 3,523,401 for 1991. In contrast to the 1970s, when there was widespread population growth, the geographical pattern of change for the late 1980s is one of widespread decline, except in the immediate hinterlands of the largest cities. The provisional estimates issued by the Central Statistics Office (CSO) in three publications are based on summaries returned to the CSO by each of the 3,200 enumerators involved in the carrying out of the census and, as such, are subject to revision. The data contained in these preliminary reports provide estimates of the total population of each county and county borough; estimates of the total number of males and females for each of 54 urban districts, 5 county boroughs, 3 new administrative units for county Dublin and 159 rural districts as well as estimates of net migration by county for the intercensal period 1986-91; and most recently a disaggregation by age groups of the estimated number of males and females in each urban and rural district. Since the spatial and temporal changes in population numbers, distribution and composition are outcomes of the dynamic processes of fertility, mortality and migration, and the economic and social processes which influence them, this paper commences with a review of the components of change. This is followed by an examination of the spatial patterns of change which result from their interaction and by a consideration of the changes which have occurred in the age composition of the population, examining how these adjustments have varied across the state. Since the demographic outcome from the 1980s is different in many respects from that of the 1970s, some of the key areas of contrast will be noted throughout.