Summary: Pursuant to a congressional request, GAO reviewed the Canadian-U.S. Free Trade Agreement's (CFTA) tariff provision for fresh fruits and vegetables and the North American Free Trade Agreement's (NAFTA) agricultural safeguard provisions between the United States and Mexico. GAO noted that: (1) the United States and Canada agreed to maintain a conditional snapback tariff mechanism for 20 years to protect against unusually low-priced imports of certain fresh fruits and vegetables; (2) the Department of Agriculture (USDA) provides the Customs Service with a list of specific tariff numbers to monitor, and Customs extracts the appropriate importer/broker data and forwards the information to USDA; (3) the United States has not applied a CFTA snapback tariff since CFTA took effect in 1989, since the required conditions of price and acreage have not been met; (4) the agricultural safeguard provision in NAFTA will pertain only to products considered as import-sensitive; and (5) the NAFTA safeguard is triggered by import volume, while the CFTA snapback mechanisms are triggered by import price.