Exchange offices in the UK have stopped selling 500 euro banknotes because of their use by money launderers.
The Serious Organised Crime Agency says 90% of the notes sold in the UK are in the hands of organised crime.
Soca deputy director Ian Cruxton said 500 euros had become the currency of choice for gangs hiding their profits.
The move means nobody will be able to buy the note in the UK - but travellers will be able to sell them if they enter the UK carrying them from abroad.