A record €130 million jackpot is at stake and must be won in tonight's Euroillions draw.
If the prize is won by just one individual, it will be the largest prize the draw has paid out. The current record is with Limerick woman Dolores McNamara who collected €115 million two years ago.
If tonight's jackpot is not won, the money will "roll down" to the next prize level where there are winners.
Euromillions is played by nine European countries including Ireland, where it is run by the National Lottery.
The second largest Lotto prize of €10,067,238 was collected by a group of winners at National Lottery headquarters in Dublin. The group bought their €6 Quick Pick ticket at the Statoil Service Station, Galway Road, Tuam, Co Galway, on Wednesday, September 12th last
The highest Lotto jackpot since the game began in 1988 was won in July 2007 by the Cunningham Family from Cork. That amount was €16,185,749.
Last Wednesday night's Lotto jackpot of €4,175,599 remains to be claimed, the National Lottery said today. The winning ticket was sold in Supermarket and Post Office, Castleshane, Co Monaghan, on September 20th.