Cambodia's official currency is the Riel, but the Cambodian economy is tied to the fate of its de facto currency, the U.S. dollar. Greenbacks can be used anywhere. The exchange rate at the time of publication was 4,100 Riel = $1. It's important to have Riel for smaller purchases, but there's no point in exchanging large amounts of foreign currency into the local scrap. Prices for all but the smallest purchases are in U.S. dollars and are thus listed in this chapter. The Thai Bhat is widely accepted in the western region of the country. You'll commonly receive small change in Riel. The Riel comes in denominations of 100, 200, 500, 1,000, 2,000, 5,000, 10,000, 50,000, and 100,000. You cannot change Cambodia's Riel outside the country, so anything you carry home is a souvenir.
ATMs -- ANZ Bank and Canadia Bank have several ATMs throughout Cambodia with reliable international service.
Currency Exchange -- You can change traveler's checks in banks in all major towns. Because the U.S. dollar is the de facto currency, it's not a bad idea to change traveler's checks to dollars for a 1% or 2% fee and make all purchases in U.S. cash.
Traveler's Checks -- Traveler's checks are accepted in most major banks for exchange, but not commonly at individual vendors. American Express is a good bet and is represented by Diethelm.
Credit Cards -- Cambodia is a cash economy, but credit cards are becoming more widely accepted. Most large hotels and high-end restaurants accept the majors, but you'll want to carry cash for most transactions and certainly in the countryside.