Based on 1990-2004 quarterly data, U.S. and E.U. demand for imported shrimp by alternative supply sources was examined within an Almost Ideal Demand System framework. For the United States, supply sources included Central America, South America, and Asia. Supply sources for the European Union included Asia, South America, and Rest of World. All own-price elasticities for the U.S. system were found to be elastic while all own-price elasticities associated with the E.U. system were found to be inelastic. With few notable exceptions, estimated cross-price elasticities suggest substitution among import sources. Finally, shrimp of Asian origin were found to be highly expenditure elastic in the US market while shrimp of South American origin were found to be the same in the European market.