Voter turnout is predicted to be low at the polls today.
The electorate has a choice of six candidates to choose from in the presidential election and polling stations are open until 10 o'clock tonight.
The referendum commission is also encouraging everyone eligible to use their democratic right today.
A Yes vote would mean deleting the reference to blasphemy in the constitution, allowing the Oireachtas to get rid of the criminal offence of blasphemy.
A no vote would leave the constitution as it is currently.