||Parts of this article (those related to 2016 census) need to be updated. (May 2017)|
The predominant religion in the Republic of Ireland is Christianity, with the largest church being the Roman Catholic Church. The Irish constitution says that the state may not endorse any particular religion and guarantees freedom of religion.
Some 3.7 million people identified as Catholic in this census (78%), 132,220 fewer than in 2011 (when the percentage stood at 84%)
In 2016, 78% of the population identified themselves as Catholic, 6% less than 5 years earlier.  The second largest Christian denomination, the Church of Ireland (Anglican), declined in membership for most of the twentieth century, but has more recently experienced an increase, as have other small Christian denominations. Other significant Protestant denominations are the Presbyterian Church in Ireland, followed by the Methodist Church in Ireland. The country's Hindu and Muslim populations have experienced significant growth in recent years, due chiefly to immigration.
In the 2016 census, 10% of the population had no religion or did not indicate a religious belief. Researchers debate the relative significance of secularisation as a general feature of Irish society, the interpretation of census results and the extent to which religious syncretism is becoming more widespread.
Originally, the 1937 Constitution of Ireland gave the Catholic Church a "special position" as the church of the majority, but also recognised other Christian denominations and Judaism. As with other predominantly Catholic European states, the Irish state underwent a period of legal secularisation in the late twentieth century. In 1972, the article of the Constitution naming specific religious groups, including the Catholic Church, was deleted by the fifth amendment of the constitution in a referendum.
Article 44 remains in the Constitution. It begins:
The State acknowledges that the homage of public worship is due to Almighty God. It shall hold His Name in reverence, and shall respect and honour religion.
The article also establishes freedom of religion (for belief, practice, and organisation without undue interference from the state), prohibits endowment of any particular religion, prohibits the state from religious discrimination, and requires the state to treat religious and non-religious schools in a non-prejudicial manner.
Despite a large number of schools in Ireland being run by religious organizations but funded by the state, a general trend of secularism is occurring within the Irish population, particularly in the younger generations. Many efforts have been made by secular groups to eliminate the rigorous study in the second and sixth classes, to prepare for the sacraments of Holy Communion and confirmation in Catholic schools. Parents can ask for their children to be excluded from religious study if they wish. However, religious studies as a subject was introduced into the state administered Junior Certificate in 2001; it is not compulsory and deals with aspects of different religions, not focusing on one particular religion.
|Irish Christian bodies|
Christianity is the largest religion in the Republic of Ireland based on baptisms. Irish Christianity is dominated by the Catholic Church, and Christianity as a whole accounts for 82.3% of the Irish population. Most churches are organized on an all-Ireland basis which includes both Northern Ireland and the Republic of Ireland.
Irish travellers have traditionally adopted a very particular attitude to the Catholic Church, with a focus on figures such as "healing priests". More generally a tradition of visions continues, often outside of Church sanction.
Evangelical movements have recently spread both within the established churches and outside them.Celtic Christianity has become increasingly popular, again both within and outside established churches.
The patron saints of Ireland for Catholics and Anglicans are Saint Patrick, Saint Bridget and Saint Columba. Saint Patrick is the only one of the three who is commonly recognised as the patron saint. Saint Patrick's Day is celebrated in Ireland and abroad on 17 March.
|Year||% of weekly church attendance in Republic of Ireland|
|Year||% of weekly church attendance among Irish Catholics|
According to a Georgetown University study, the country also has one of the highest rates of regular Mass attendance in the Western World. While daily Mass attendance was 13% in 2006 there had been a reduction in weekly attendance from 81% to 48% between 1990 and 2006, although the decline was reported as leveling off. In the 1970s a survey had given figures at 91%. In 2011, it was reported that weekly Mass attendance in Dublin was on average 18%, with it being lower among younger generations and in some areas less than 2%. A 2012 survey of Irish Catholics undertaken by the Association of Catholic Priests found the weekly mass attendance rate to be 35% on an all-island basis, while daily mass attendance was reported at 3%.
A 2006 Dentsu poll found that 7% of Ireland had no religion. According to Greeley (2003), 5% of those in Ireland do not believe in God, but only 2% accept the self-identification of "atheist." According to Ingelhart et al. (2004) and Davie (1999), 4% of the Irish do not believe in God.
In a 2007-2008 Gallup Poll, 42% of Ireland answered no to the question "Does religion occupy an important place in your life?" and in the 2011 Gallup, 53% of Ireland answered no.
A 2010 Bishops Conference survey found that 10.1% of Irish Catholics did not believe in God.
According to a 2012 WIN-Gallup International poll, Ireland had the second highest decline in religiosity from 69% in 2005 to 47% in 2012, while those who considered themselves not a religious person increased 25% in 2005 to 44% in 2012. The poll also showed that 10% of Ireland now consider themselves convinced atheists, which is an increase from 2005.
There are 49,204 adherents (1.06%) of Islam in Ireland as of 2011. Irish Islam has a 60 year long and complex organisational history. Islamic new religious movements such as Fethullah Gulen are also represented in Ireland.
The population of Buddhists in Ireland is 8,703 (0.19%). Irish Buddhists such as U Dhammaloka are recorded from the late nineteenth century on, with numbers growing particularly in the 21st century. Beyond formal membership in Theravada, Mahayana, Vajrayana and Western Buddhist groups, there is increasing syncretism, with self-identified Christians and others using Buddhist meditation techniques, Buddha images, texts by figures such as the 14th Dalai Lama and so on. Reputed links between Buddhism and Celtic religion have long played a role in Irish literature.
Various Neopagan movements are active in Ireland, especially Wicca, Neo-druidry and Celtic Polytheism. Ireland is also a significant point of reference for various kinds of Celtic  and other neo-pagan spirituality and religious practice around the world, such as the Fellowship of Isis.
New Age religious movements are becoming increasingly significant in Ireland, often as a form of syncretism for members of established religions. Participation is strongly gendered, with a high proportion of women. A typical example is A course in miracles.
Between 2006 and 2011, Catholics decreased as a percentage of the population, but still showed a robust increase in absolute numbers due both to an excess of births over deaths as well as immigration from countries such as Poland. Most recently, Protestantism, including the Church of Ireland, has experienced a slight decrease in percentage, despite having earlier experienced some recovery. Those declaring no religion, Eastern Orthodoxy, and Islam showed significant increases. The results of the 2011 census were as follows:
|Religion||Number 2006||Percent 2006||Number 2011||Percent 2011||Number 2016||Percent 2016|
|Christian religions[tabnote 1]||3,922,386||92.51||4,149,665||90.44|
|Church of Ireland||121,229||2.86||129,039||2.81||126,400||2.65|
|Latter Day Saints (Mormon)||1,237||0.03||1,284||0.03|
|Quaker (Society of Friends)||882||0.02||925||0.02|
|Other Christian religions||29,206||0.69||41,161||0.90||37,400||0.79|
|Non-Christian religions[tabnote 1]||57,838||1.36||87,157||1.90|
|Non-religious (inc. lapsed, atheist, agnostic)[tabnote 1]||189,302||4.46||278,516||6.07|
Going by the recent 2016 figures,
According to a 2012 Eurobarometer Poll when people were shown a card listing options for religious identification: