The developing countries emerging market crisis during the second half of 1990s has had a major impact on changing the views of academicians, policy designers and developing countries’ authorities with respect to exchange rate policies, particularly after the Asian Financial Crisis in 1997. Although the Asian Financial Crisis has brought enormous damage to those hit countries, it left very precious lessons for the developing countries. Countries have to make a decision under uncertainty-they must choose an exchange-rate system and associated monetary policy without full information on the onsequences of that choice. They must weigh the arguments and the costs of errors from adopting different exchange rates. They must evaluate the alleged benefits of each system and the opportunities for achieving those benefits through alternative, substitute means. They must also evaluate methods of reducing the potential costs of each system. It is true that no single exchange rate regime can be prescribed as best for all, nor is the best choice of exchange rate regime always clears for all places in all times, even in light of their specific circumstances. There are no simple, universal answers. But under most circumstances and for most developing countries, one system of flexible exchange rate is better than others.