The Polling Stations across Ireland opened at 7am this morning.
A high turnout of young people and women is expected to cast their ballot up to 10pm tonight.
At one rural station this morning, Knockminna National School near Ballymote, pictured, just one person had voted by 7.15am. The lady cast her ballot on her way to work.
More than three million people are eligible to vote in the first referendum on the Eighth amendment in 35 years. In the Northwest almost 220,000 people are eligible to vote.
When the Eighth Amendment was introduced in 1983, it gave equal rights to a woman and her unborn child which amounted to a ban on abortion. Previous referendums have dealt with issues such as allowing women to travel and whether suicide was considered a serious risk to a mother's life.
But campaigners have long sought the outright repeal of the Eighth. The Government committed to holding the referendum after the last election.
So what are we being asked to vote on?
Voters have to decide if they want to repeal the Eighth Amendment from the Constitution and allow the Oireachtas to legislate for terminations.
If there is a Yes, will abortion automatically become legal?
No, unless and until the Oireachtas introduces legislation permitting abortions in Ireland it will remain illegal.
Even if the referendum passes, the Protection of Life During Pregnancy Act 2013 stays in place. It allows for terminations only if there is a serious threat to the life of the mother.
When would the Government legislate?
Health Minister Simon Harris has indicated he would like to bring legislation before the Dáil ahead of the summer recess in July. The target would be to have a GP-led abortion service legalised by the end of the year - but this might be ambitious.
What does a GP-led abortion service mean?
The Government has said it does not want to see abortion clinics set up in Ireland. Instead, it is proposing to allow GPs prescribe an abortion pill on request up to 12 weeks into a pregnancy. A 'pause period' of 72 hours would apply between when a women first sees her doctor and receives the pill.
What about after 12 weeks?
Abortion will remain illegal after 12 weeks except in a number of limited circumstances.
These include where there is a risk to the life, or of serious harm to the health of the pregnant woman, without a distinction between risk from physical or mental health. The minister has said 'serious harm' would go well beyond the expected and common complications of pregnancy, and other common chronic conditions that may be exacerbated by pregnancy.
Who decides what is 'serious harm'?
Two medical practitioners would have to certify that in their reasonable opinion (a) there is a risk to the life or of serious harm to the health of the pregnant woman, (b) the foetus has not reached viability and (c) the termination of pregnancy is appropriate to avert the risk.
One of the medical practitioners would have to be an obstetrician and the other a medical practitioner appropriate to the clinical circumstances of the case.
What if the foetus has reached viability?
If doctors believe the foetus is capable of sustained survival outside the uterus, they are duty bound to deliver it.
What have been the main arguments made by the Yes side during the campaign?
Yes campaigners have argued that abortion already exists in Ireland but it is unsafe and unregulated. They say nine women travel to the UK every day to procure an abortion. Another three order abortion pills online. The Yes side have also talked a lot about the 'hard cases' such as rape, incest and fatal foetal abnormalities.
They believe it is not right for a rape victim or a woman whose child has no chance of survival outside the womb to be forced to continue the pregnancy for the full term.
What have the No side been arguing?
No campaigners have said the proposals currently on the table amount to "abortion on demand". They note that a woman will not have to give any reason for seeking an abortion in the first 12 weeks.
They also argue that the conditions for procuring a late-term abortion are not restrictive enough. Among the fears being raised is that babies diagnosed with disabilities while in the womb will be aborted. In the final days of the campaign, the No side has told voters that a better regime can be adopted.
If there's a No vote, will the Government go back to the drawing board?
This is being described as a "once in a generation" vote. The Taoiseach has said nothing can change unless the Eighth Amendment is repealed. He has also claimed 12 weeks is the best option possible because there is no way to specifically legislate for abortion in rape cases.
What do the polls say?
All the polls have pointed to a Yes vote. A 'wisdom of the crowds' technique predicted 56pc in favour of Yes versus 44pc for No. But neither side is putting too much faith in the pollsters. Turnout will be key, especially in terms of young versus old and rural versus urban.
What will the ballot paper say?
The ballot won't mention 'abortion' or even the Eighth Amendment. It will ask whether you approve of the proposal "to amend the Constitution contained in the undermentioned Bill" which is the "Thirty-sixth Amendment of the Constitution Bill 2018". If you vote Yes it means you want to repeal the Eighth. If you vote No, it means you want to retain the status quo.
Mark an X next to your choice.
Do not write anything else on the card as it could be seen as a spoiled vote.
Your voting card will tell you where your polling station is.
If you have not got a voting card, you can still vote as long as you are on the register of electors.
In that case bring your ID to the centre to be allowed to vote.
No videos or photos, including selfies, can be taken in the polling station.
You also should not wear any jumpers, badges or merchandise promoting either side when you go to the station to vote.
The Referendum Commission has called on voters to inform themselves about the issues around the referendum and to use their vote. See above.
Chairperson of the Referendum Commission, Ms Justice Isobel Kennedy said: “The Referendum Commission does not campaign for a yes or a no vote, but we do strongly urge you to inform yourself and to use your vote.
"How you vote on this issue is entirely a matter for you to decide, but it is important that you take the opportunity to use your vote.”
Additional: Irish Independent