The question on religion in this year's Census will be different for the first time in 14 years.
The traditional wording of 'what is your religion' has been replaced by 'what is your religion, if any?'.
Tomorrow's the day people are due to fill in their forms and anyone who has yet to receive one's asked to contact the CSO directly.
Senior Statistician with the CSO, Cormac Halpin, says people have a number of options when answering the question on religion:
"The guidance we're giving is to tick the box or write in how you feel about your religion on Census Night. So I wouldn't possibly try to describe the nuances of people's belief or lack of belief. It's really up to people's own judgments to describe their religious beliefs on Census Night. So if you feel that the Catholic component of that is predominant, you might tick Catholic; if youfeel the atheist is predominant, you might take the no religion box".