Starting in 2013, the ECB in Frankfurt has slowly been working through the euro notes from the €5 up to the €10 and the €20, attempting to make them harder to counterfeit.
On Tuesday they unveiled the new €50 note, saying the re-designed bill would help battle fraud and demonstrate the bank's commitment to cash.
"State-of-the-art security features help protect our money," ECB executive board member Yves Mersch said in a statement.
The new-look €50 note boasts a transparent window with a holographic portrait of the Greek mythological figure Europa and a so-called "emerald number" that changes colour from green to blue when viewed at different angles.
Complex visual features like these are supposed to make identifying counterfeit bills quicker and easier.
But the head of the German Police Union (DpolG) told Spiegel that the new note can in no way be described as forgery-proof.
The new security features “might lead to forgeries being more easily identified and make the life of police easier,” said DpolG boss Rainer Wendt.
But it would be dangerous to give the impression that these new notes are somehow 'unforgeable', he asserted.
“They’ll find a way to forge even these notes.”
The €50 bill is the most widely used note, accounting for around 45 percent of the total number of euro banknotes in existence, meaning there are more of them in circulation than the three smaller denominations put together.
Because of this, the note is the jackpot for all money forgers. The €50 is forged more than any other paper bill produced by the ECB in Frankfurt.
2015 was a record year for authorities finding fake notes in circulation. The ECB counted 899,000 that had been pulled out of circulation, the highest since the euro was introduced in 2002. Half of the forgeries were €50 notes.