The Irish pound is in its final day of being the sole official currency of the State.
From midnight, euro notes and coins will replace national currencies in 12 of the 15 EU member-states in the biggest monetary changeover in history.
The ECB has printed 15 billion bank notes and minted 51 billion coins, to a total value of €646 billion (£508 billion). Two thirds of them have already been delivered to banks and retailers and police throughout Europe are on high alert to prevent robberies.
The Irish pound will no longer be tradeable after February 9.
To facilitate the changeover cash machines around the country will shut down at midnight to allow them to be loaded with euro notes.
Ireland is the only country of the 12 participating 'euro states', where prices will be rounded up - for example, a pint of Guinness will cost €3 on average. However, the Euro Changeover Board has expressed confidence that consumers realise that goods will not actually become more expensive.
The president of the European Central Bank, Wim Duisenberg, said the launch represented the dawn of a new era.
"By using the euro notes and coins we give a clear signal of the confidence and hope we have in tomorrow's Europe," he said.
The euro was introduced in 1999, when national currencies were pegged to it at fixed rates and ceased to be traded independently on currency markets.