The CSO is assuring people that the confidentiality of the data provided is guaranteed by law
Tonight is Census Night, where everyone is obliged to fill out their forms.
The Census provides up-to-date information at local, regional and national levels.
Population statistics are necessary for planning the provision of health care, education and employment, while regional data informs government policy.
You can find out more information on Census.ie, where you can still request a census form if you have yet to receive them.
Director General of the Central Statistics Office (CSO), Padraig Dalton, spoke to Colette Fitzpatrick this morning.
He explained that "the most important thing for me to tell everyone is that the confidentiality of the data that is provided to the CSO is guaranteed by law. So legally the CSO is not allowed to provide this information to anyone outside the CSO.
"The second thing I'd like to say to people is that the data that is provided can only be used for statistical purposes," he added.
Census 2016 will ask everyone in Ireland what religion they are, with "no religion" one of the options available.
The Humanist Association of Ireland is asking people to think before they tick a religion box.
Deirdre Cullen with the CSO says people's answers should reflect their beliefs. There are five religions listed alongside the 'no religion' box.
"If your religion isn't added, but you have a religion, you can write it in in the write-in boxes," she explained.