Official figures from the Central Statistics Office show that the birth rate is at its highest level since its records began 51 years ago.
The CSO says there were 19,950 births registered in the first three months of this year, which was a 7.6% increase on the same time last year.
"This is the highest number of births registered in a quarter since the series began in 1960," it said.
"Births in the first quarter of 2011 represented an annual birth rate of 17.8 per 1,000 population. The rate for the corresponding quarter of 2010 was 16.6 per 1,000 population and 15.6 per 1,000 population in quarter 1 2002."
Fingal in Dublin had the highest birth rate, while South Tipperary had the lowest birth rate.
The CSO figures show that there were 6,768 births outside of marriage in the period.
Limerick City had the highest percentage of births outside marriage at 52%, while Leitrim had the lowest at 21%.
There were 7,651 deaths in the first three months of 2011, which was an increase of 1.2% on January to March 2010.
As a result, the CSO says that natural increase in the population was 12,299.