People are being asked to think before they tick the religion box on Census night.
A number of groups are reminding people the information is used for planning things like what schools to build and who should control them.
Census Night is this Sunday, when every person in the country is legally required to fill out their form. Every five years, the comprehensive survey is carried out to help plan for the future of the country - in terms of schools, buses, hospitals and many other services.
The Humanist Association of Ireland is asking everyone to think before they tick when it comes to the question on religion, because of the implication on access to schools.
Deirdre Cullen from the Central Statistic Office said the information is confidential, and is only used for statistical reasons "it covers so many aspects that it's used by a wide variety of people."
"Not only by the Department of Education to plan for schools, but if anybody wants to put on a new bus route, train line or Luas tracks they have to go to Census data to see where people live and work and the list goes on".
In planning for services including schools, one question that’s asked is 'What is your Religion?'
In 2011, 3.8 million people ticked the Roman Catholic box, while 270 thousand chose no religion. The Humanist Association has been asking people to consider their choice based on how they practice religion today.
Spokesman, Brian Whiteside, said "just give it a little bit of thought, and don't mark a religion just because you were born into that religion."
"Just think for a moment 'what am I?' One of the statistics that we always quote is the number of couples choosing to have non-religious weddings. It's about one third of couples, and that is not reflected in what we see in the Census".
Deirdre Cullen welcomes that conversation "There's been a lot of debate about the religion question on the Census and that is a good thing because it's making people sit back and think about it before they answer it".
"There's also been discussion around adult children in the home who perhaps don't want to tell mammy and daddy that they no longer have the same religious beliefs as their parents".
"That is dealt with by providing people with a privacy envelope and their pwn individual form".
If anyone has any questions the Census helpline will be open all weekend on 1850201604.
