The Foreign Operations Act (P.L. 102-391) signed on October 6, 1992 allows the U.S. quota, or contribution, increase to the IMF of $12 billion to be used to "...support monetary stability in member countries through the instrumentality of currency boards." What is a currency board? How does it differ from an alternative monetary arrangement such as a central bank? Why was it adopted by countries with histories of chronic inflation (e.g., Argentina) and those emerging from the Soviet bloc (e.g., Bulgaria), and urged upon those suddenly hit by currency speculation (e.g., Indonesia)? What role did the currency board play in Argentina's 2001-2003 financial difficulties and why was it abandoned? Although factors affecting the decision to adopt a currency board vary from country to country, as do outcomes, fundamental differences between currency boards and central banks remain constant. This report focuses on their differences to provide a foundation for evaluating disparate cases. To understand the differences, it should be noted that the most important function of a central bank is its ability to alter the supply of money. When this power is abused, as occurs when central banks must provide the monetary wherewithal to finance government budget deficits, it undermines the functions that money performs in a market economy: that of a unit of account, medium of exchange, and store of value. History is replete with episodes of such an abuse of monetary policy. The most egregious consequences of abuse are to be found in episodes of hyperinflation with prices rising daily. Countries have sought a variety of monetary arrangements to curtail abuse in the issuance of money. A significant example is a currency board. Currency boards now function in Bulgaria, Hong Kong, Djibouti, Lithuania, Estonia, and Brunei, and are promoted by some economists as a means for developing countries to achieve macroeconomic stability. The sole function of these boards is to issue currency (and coins) that are 100% backed by a commodity (e.g., gold and silver) or by the stable valued currency of another country. A currency board is forbidden from altering the amount of currency by buying or selling assets denominated in domestic money. As a result, the currency it issues is "safe" or of stable value (or as stable in value as the currency to which it is linked), and this stability would contribute to the vital role money plays in market economies. A currency board arrangement is very similar in nature to the formal adoption of another country's currency, popularly known as "dollarization." Using a currency board has a potential downside for a country. It is exposed to every shock that affects the exchange rate of the country to which it has tied its currency, and prevents the use of monetary policy to counter those shocks. Argentina is a recent example of what can happen in a currency board country. Argentina linked its currency to the U.S. dollar. The large appreciation of the dollar between mid-1995 and 2002 had a severely depressing affect on the Argentine economy which led to the abandonment of the currency board and economic crisis. Unlike central banks, currency boards also lack a lender-of-last-resort function. In a financial crisis, currency boards would be unable to lower interest rates and lend banks money to quell bank runs. This report will not be updated.