Spain, where the euro has been welcomed with open arms by almost 70 per cent of the people, is one of Europe's most enthusiastic members.
Although Spaniards can use the peseta alongside the euro until the end of February, the vast majority are expected to pay with the new currency within a few weeks.
It has been estimated that over 70 per cent of euro notes will be distributed by automatic cash machines which are used by the majority of Spaniards. Almost a quarter of the 190,000 cash dispensers in Europe can be found in towns and villages across the country, and an estimated 75 percent of them had been converted by yesterday morning.
Taking a walk around the streets near my home in Madrid at midday yesterday I counted seven out of eight cash machines distributing euros to queues of people - many of them armed with their pocket converters. The remainder of the machines are expected to be converted when the banks open for business this morning .
One of the early customers at his local cash dispensing machine was the Economy Minister, Rodrigo Rato. He put his card in and withdrew 120 euros before going into a local cafe for a breakfast coffee. But when he paid with a 50 euro bill, he was asked to autograph the note to be framed as a souvenir of a historic day.
New Year's Day is a traditional holiday in Spain, with nearly all shops and offices remaining closed. But more than 900 bank offices opened for business for three hours yesterday to meet the demand for the new currency. There were long queues at some of them; many of the customers were the owners of small businesses and taxi-drivers requiring euros to give as change, but many came out of curiosity.
"I didn't have anything better to do, so I decided to come along with the kids," said one client in a Madrid bank.
The arrival of the euro has caused concern among the many Spaniards who had accumulated millions of pesetas kept hidden from the tax authorities. There has been a big increase in the number of people buying expensive cars and property, much of it paid for in hard cash as a way of spending their black pesetas.