The number of babies born between July and September last year was the highest for nearly 30 years.
According to the Central Statistics Office, there were 19,289 births registered in the third quarter of 2009.
Read the full CSO report
That is the largest number of births registered in a quarter since the period April to June 1980, when 19,339 births were registered.
The 19,289 births registered represented an increase of 1.6% on the same period in 2008.
The highest birth rate was recorded in Fingal in Dublin, while the lowest rate was in Co Monaghan.
Just over one third of all births were registered as outside marriage.
The greatest percentage was recorded in Cork City were nearly half of all births were outside marriage. The lowest percentage was in Co Leitrim at 20%.
While the birth rate is increasing, the death rate is decreasing, with 6,638 deaths registered between July and September, a decrease of 0.5% on the same period for the previous year.
There was also a drop in the number of marriages registered. 8,050 marriages were registered in July, August and September of last year, 715 less for the same months in 2008.