Under the terms of the treaty, each country had to concede most-favoured-nation* treatment to all other parties. Each signatory State also granted tariff concessions to the other parties, that is, they limited the customs duties imposed on the importation of foreign goods.

Signatory States were obliged not to take certain measures that would result in obstacles to international trade. In practice, this type of obligation amounted to a code of good conduct in trade, which Member States undertook to adhere to when they joined the General Agreement. This was principally designed to prevent discrimination between national products and imported products, to regulate the use of anti-dumping measures, to prohibit quantitative restrictions to trade, and to regulate subsidies.

Depending on the specific situation and particular characteristics of each State, some exceptions to these obligations were agreed. Certain sectors, namely services, agriculture and textiles, were largely excluded from the scope of the General Agreement. Some States also enjoyed the benefit of special rules. Since the signature of the General Agreement in 1947, developing countries had frequently pointed out that the general principles of the GATT worked against them. But their grievances were not acknowledged until the first United Nations Conference on Trade and Development (UNCTAD) in 1964, when the principle of differential treatment was invoked. UNCTAD has since become a subsidiary body of the United Nations General Assembly, well known for defending the economic interests of developing countries.