The Islamic leader in Ireland Sheikh Hussein Halawa said more than 40 nationalities make up the 19,147 Muslims.
He said the four-fold increase since the 1991 Census began to manifest itself between 1993-96 with the arrival of refugees from war-stricken European states such as Bosnia.
“Previously, the Muslim community in Ireland was largely single men but, in recent years, there are many families living here with many of their children now born here,” Sheikh Halawa said.
The influence of migration trends showed a percentage decline in Roman Catholic numbers while a long-term fall in numbers recorded as Church of Ireland, Presbyterian and Methodist was reversed.
The census showed an increase of more than 234,000 people in the Roman Catholic population which grew by 7% to 3.4 million. The religious demographics point to an overall decline in Roman Catholics from 91.6% in 1991 to 88.4% last year.
The number of Church of Ireland members was up 29% from 89,200 in 1991 to 115,600 in 2002 with immigrants comprising 19,000 of the overall increase of 26,424.
Sizeable increases were also noted in numbers recorded as Methodist - up 5,000 to 10,000 - and Presbyterian - up 7,400 to 20,000. In addition to Muslims, one of the most dramatic increases was in Orthodox adherents - from 358 in 1991 to 10,437 last year.
The CSO advised that in interpreting the changes in the number of adherents to various religions account should be taken of the different question formulations used in the two censuses.
Those not stating a religion fell by 5.1% while the number stating no religion increased by 100% to 138,264. Those classified as atheist stands at 500, up 56%.
Jehovah’s Witness, Buddhist and Evangelical are also in the top 10 religions practiced in Ireland.