Cambodia has been using the US dollar since the collapse of the Khmer Rouge. International aid flooded into the country after Pol Pot’s regime finally gave up on their civil war. This international aid came in the form of over a billion US dollars.   The Khmer Rouge destroyed the Cambodian banking system and removed all money from the country – not just the physical notes but the concept of money as a way to trade value without trading goods.  Even after being reinstated, public confidence in the Cambodian riel is much lower than in US dollars, so people choose to keep their savings in dollars. Until this public confidence changes, the US dollar will remain the most powerful currency in Cambodia.