Diplomatic relations were established between the USSR and Yugoslavia on June 24, 1940. Previously, on May 11, 1940, the two countries had signed a treaty on trade and navigation, a protocol concerning trade missions, and an agreement on trade and payments for the period 1940–41.
As the danger of aggression from fascist Germany and Italy increased, the USSR and Yugoslavia signed a treaty of friendship and nonaggression on Apr. 5, 1941. On April 6, however, Yugoslavia was invaded by the fascist states, and relations were broken off. In the course of the 1941—45 war of popular liberation in Yugoslavia, the National Liberation Committee was created, and it received comprehensive Soviet support and military and material assistance. After the formation on Mar. 7, 1945, of the provisional people’s government of Democratic Federative Yugoslavia, the two countries concluded a treaty of friendship, mutual assistance, and postwar cooperation on Apr. 11, 1945. Soviet-Yugoslav relations were based on the principle of socialist internationalism.
After the war the two countries signed agreements on economic cooperation (June 8, 1946), on mutual deliveries of goods (June 8, 1946), and on the creation of a Yugoslav-Soviet joint-stock shipping company on the Danube (Feb. 4, 1947). The treaty of Apr. 11, 1945, became invalid after the breach of Soviet-Yugoslav relations on Sept. 28, 1949.
In the mid-1950’s the two countries concluded agreements on trade and payments (Jan. 5, 1955), on air transportation (Sept. 3, 1955), and on scientific and technical cooperation (Dec. 19, 1955). In a joint declaration of June 2, 1955, both sides supported the development of bilateral and international cooperation. A joint declaration of June 20, 1956, and a joint communique of Oct. 3, 1962, noted that the 1955 declaration serves as a basis for the development of friendly relations between the two countries.
Among the agreements between the countries in the 1960’s was one under which the USSR supplied, as a gift to Yugoslavia, a plant producing large-panel units for housing, to be used to help in the reconstruction of the city of Skopje, destroyed by an earthquake (Aug. 19, 1963). In addition, the two sides concluded agreements on technical assistance to Yugoslavia for the construction of metallurgical works in Smederevo (Nov. 26, 1963) and on technical assistance to Yugoslavia for the construction of thermal power plants (Nov. 26, 1964). On June 7, 1965, the two countries concluded an agreement that provided for the creation of an intergovernmental committee for economic cooperation and another agreement that granted Yugoslavia a loan to underwrite Soviet technical assistance for the reconstruction of Skopje. Other agreements during the period included those on mutual deliveries of goods (May 19, 1966) and on technical assistance for the construction and expansion of nonferrous and ferrous metallurgical plants, energy-producing facilities, and other industrial facilities in Yugoslavia (Aug. 28, 1966).
In a joint declaration of Sept. 25, 1971, both parties reaffirmed their decision to develop industrial cooperation and specialization in the most technologically advanced areas. A joint communique of June 10, 1972, stressed that the ideas expressed in the 1971 declaration had been applied with positive results. In a joint communique of Oct. 1, 1973, both sides noted the successful development of comprehensive cooperation.
On May 24, 1974, the countries concluded an agreement on cooperation in science, culture, and education. On Apr. 11, 1975, agreements were concluded on cooperation in the peaceful use of atomic energy, on mutual deliveries of ships and shipping equipment for the period 1976–80, and on long-term cooperation in the production and delivery of light motor vehicles and spare parts for the period 1976–80.
V. M. ZIMIANIN