To evaluate the often stated proposition that agricultural protectionism has reduced market access for agricultural exports worldwide, this report examines market penetration of importing country markets by exporters of corn, soybeans, beef and veal, tobacco, wheat, rice, and cotton in 1970-82.' Results indicate that, with the exception of the European Community's variable import levy on corn, soybeans, corn, and cotton markets are relatively open and that protection for beef and veal has been limited primarily to the developed countries. Lower rates of market penetration growth by exporters of wheat and rice are indicative of higher levels of protection and producer support in importing country markets. Trade negotiations to increase market access for U.S. agricultural exports should therefore concentrate on the more restricted commodity and country markets.