However, the full replacement of Lithuania's national currency will be gradual, according to the Commission.
For two weeks, Lithuanians will be able to withdraw and use cash in both euros and litas, but change will only be dispensed in euros.
"This has been made possible thanks to thorough preparations ahead of the introduction of the single currency," the Commission said on Wednesday, noting that Lietuvos Bankas, the central bank of Lithuania, had already given euro banknotes and coins to the country's commercial bank.
Lietuvos Bankas in turn will exchange "unlimited amounts of litas" for the euro at a rate of about 3.4 litas against the euro. Commercial banks, too, will also provide free services for the exchange of unlimited sums of cash, though only until the end of June 2015.
Prices displayed in both euro and litas, which has been in force since August, will stay in effect until June 2015.
The European Commission announced Lithuania's accession to the euro zone in June 2014, after rendering a positive evaluation of the member state's compliance with the criteria to switch to the euro.
The euro zone consists of Austria, Belgium, Cyprus, Estonia, Finland, France, Germany, Greece, Ireland, Italy, Latvia, Luxembourg, Malta, Netherlands, Portugal, Slovakia, Slovenia, and Spain. The currency was introduced in 1999 and its name was decided upon in 1995.
