The paper examines the effects of exchange rate fluctuations on real output and prices in a sample of 33 developing countries. The theoretical model decomposes movements in the exchange rate into anticipated and unanticipated components. Unanticipated currency fluctuations determine aggregate demand through exports, imports, and the demand for domestic currency, and determine aggregate supply through the cost of imported intermediate goods. Anticipated exchange rate depreciation, through the supply channel, has limited effects on output growth and price inflation. Unanticipated currency fluctuations appear more significant, with varying effects on output growth and price inflation across developing countries.