The total population of the State is now estimated at 3.98 million, the highest figure since 1871 when the census recorded a population of 4.05 million, according to the Central Statistics Office.
Figures for April 2003 show the population increased by 61,700 or 1.6 per cent on the 3.92 million recorded in the 2002 census.
Net immigration contributed 29,800 of the most recent annual increase, while births exceeded deaths by 31,900, the CSO said.
The estimated number of immigrants in the year to April 2003 was 50,500, while 20,700 people emigrated in the same period.
Both figures were down on the previous twelve month period. Immigration peaked at 66,900 in the twelve months to April 2002, according to the figures. Emigration is now at its lowest level since the current records began in 1987.
A total of 35 per cent of all immigrants are nationals of countries other than EU states and the US. The same percentage of immigrants are returning Irish nationals.
Some 40 per cent of the State's emigrants went to countries other than the EU and the US.