Active involvement of modern Russia in information wars requires a thorough study of the foreign policy of the Soviet Union in order to avoid repeating the mistakes of the past and strengthening Russia’s position in modern affairs with fair arguments from the past. The rough foreign policy of the Soviet Union in the late 1970s, the invasion of troops into Afghanistan and the condemnation of this action by a large part of the world community caused in the world a feeling of special aggressiveness of the Soviet Union and its imperialist ambitions. In this context, of great interest is the little-studied foreign policy of the USSR in Indochina during the Third Indochina War (1975-1990), where Vietnam’s military actions against Cambodia were perceived by China as a part of the Soviet ‘socialist imperialism’. The article attempts to clarify whether the policy of the USSR in Indochina actually had an imperialistic character or it is a myth. After the many years of ideological and political confrontation, relations between the PRC and the USSR were in deep crisis. The development of relations between the USSR and Vietnam, and namely the 1978 Treaty of Friendship and Cooperation between the countries was perceived by China as an attempt of the Soviet Union to gain through Vietnam a base on the southern borders of China. After the Vietnam invasion of Cambodia in December 1978, the Sino-Vietnamese War (February-March 1979) began. The military conflict did not last long, but relations between the countries remained tense and began to normalize only after the withdrawal of Vietnamese troops from Cambodia in 1989. The geopolitical ambitions of Vietnam within the borders of the former French Indochina were in the interests of Moscow in the context of creating a rival to China on its strategic southern direction. The emergence of the Indochinese Federation would certainly be a distraction for China and, in this connection, would contribute to strengthening of the security of the Soviet Far East. However, it is arguable to what extent Vietnamese expansionism was a part of the Soviet strategy as it was seen in the PRC. Firstly, in the Treaty on Friendship and Cooperation between the USSR and the Socialist Republic of Vietnam of 3 November 1978, the part relating to mutual assistance in the event of war, discusses only mutual consultations, and mentions no USSR’s obligations to protect Vietnam, which shows little interest of the Soviet Union in Indochina. Secondly, the minor importance of the Vietnamese direction of the anti-Chinese policy of the USSR is reflected in the low degree of military presence of the USSR in Vietnam during the Sino-Vietnamese War. Thirdly, the attitude of the USSR towards Indochina is reflected in the nature of the Soviet base in Cam Ranh leased from Vietnam, which, as this article argues, was not an offensive element of the USSR in Indochina, but represented a transshipment point of the USSR Navy on its way to the Indian Ocean and southern part of the Pacific Ocean. The above arguments show that the China propagandized Soviet ‘socialist imperialism’ in Indochina was nothing more than a myth emerged from the PRC’s fear of the Soviet Union and used by China in an information struggle to eradicate the Soviet influence in the strategically important to China regions of the South China Sea and the Indochina Peninsula.