The current exchange rate is US$1 = 4,200 Riel, although this often changes and market level is still working at US$1 = 4,000 Riel as this computes more easily. You will often get change in both currencies: keep some Riel for small transactions and remember that big notes are difficult for some people to change. A tiny rip in a US dollar will be rejected by almost everyone, although ancient and bedraggled Riel are accepted everywhere.

There are plenty of banks now, including the recent arrival of ANZ Bank in Phnom Penh and elsewhere, with ATMs now coming in too. You can use Western Union also, and draw out funds from credit cards. However, credit cards are usually not accepted as payment, unless you are in up-market or international places. Travelers’ checks can be changed at most banks for a fee of around 1-4%. Business hours are, as with everywhere else, from around 8am to 12pm and 2pm to 5pm (Cambodia takes a break from 12 to 2 every day).