Canada was one of several multilateral trade groups operating in coordination with GATT, including the Organisation for Economic Co-operation and Development (OECD), the quadrangle group and the Cairns Group of Fair Trading Nations. Membership in these groups has allowed Canada to influence the direction of trade negotiations. The General Agreement on Tariffs and Trade was a free trade agreement that eliminated tariffs and increased international trade. As the first multilateral free trade agreement, GATT governed an important part of international trade between January 1, 1948 and January 1, 1995. The agreement ended with the more robust World Trade Organization (WTO) replacement. In addition to a 15% to 18% reduction in tariffs on agricultural and food products. In addition, the chemical negotiations resulted in an interim agreement on the abolition of the US selling price (ASP). This was a method of assessing certain chemicals used by these countries for the institution of import duties, which gave domestic producers a much higher level of protection than indicated under tariff conditions. In May 1963, the ministers agreed on three negotiating objectives: this part of the result was not authorized by Congress, and the U.S. selling price was not abolished until Congress adopted the results of the Tokyo Round. The results in agriculture as a whole have been poor.

The most notable achievement was the agreement on a Memorandum of Understanding on the basic elements for the arrangement of global subsidies, which was eventually incorporated into a new international agreement on cereals. Quantitative import and export subsidies were generally prohibited by the GATT, but exemptions were permitted in certain circumstances. The two main exceptions for Canada were macro-financial assistance and agricultural regimes. These latter products have been excluded from the GATT trade liberalization framework, mainly due to the insistence of the United States. Canada and other major exporters of agricultural products have strongly opposed the absence (see agriculture and food). Canada also opposed the special waiver that the United States received in 1955 to limit imports of dairy products when it did not have national controls on production. Subsequently, after many controversies, Germany and Switzerland obtained other exceptions to limit agricultural imports. When the Dillon cycle went through the laborious process of collective bargaining by post, it became clear, well before the end of the cycle, that a more comprehensive approach was needed to address the emerging challenges arising from the creation of the European Economic Community (EEC) and EFTA, as well as to make Europe a major international distributor in general. The GATT had three main provisions.

The most important requirement was that each member be obliged to confer the status of the most favoured country on any other member. All members must be treated the same with respect to tariffs. It excluded special tariffs between members of the British Commonwealth and the Customs Union.