It is decision day on whether the UK will remain a member of the European Union or leave.
Polling stations are open from 7am until 10pm and figures show more than 46 million people have registered to have their say in the historic vote, including just over 1.2 million in Northern Ireland.
Voters in Northern Ireland must have valid photographic ID.
The following forms of ID can be accepted at the polling station:
- A UK or Irish passport
- A UK, Irish or EEA driving licence
- A Translink Senior Smartpass
- A Translink 60+ Smartpass
- A Translink War Disabled Smartpass
- A Translink Blind Person's Smartpass
- An Electoral Identity Card
The identification does not need to be 'current' but the presiding officer at the polling station must be satisfied that the photograph matches that of the person intending to vote.
Voters will be asked: "Should the United Kingdom remain a member of the European or leave the European Union?" and should mark a cross in the box of their choice.
If you make a mistake on the ballot paper, you can ask for another one.