when did the euro currency start
[Last update: 7-Dec-2001]. On January 1, 1999, eleven European countries have replaced their national currencies and introduced a single European currency, the euro. Today (December 2001) the euro is the official currency in 12 countries. Bills and coins of the national currencies will remain in circulation as subdenominations of the euro until January 1, 2002, when they will be exchanged against new euro coins and bills.