Soviet-Finnish relations during “Cold War” were based on the “Treaty of Friendship, Cooperation and Mutual Assistance between the USSR and Finland” signed in 1948. There were not many disagreements in the issues of keeping peace and stability between Finland and the USSR in 1950s — 1980s as Finland traditionally followed the policy of neutrality and non-alignment and the USSR tried to uphold the reputation of a peacemaker in the international community. Regional cooperation — ties between Finland and Karelia — played a significant role in Soviet-Finnish relations of that period. A big part of the article is devoted to the problem of boundary. During the first post-war decade it was actually closed for those Soviet people (primarily, ethnic Finns) who wanted to leave for the neighboring country. The situation began to change from the mid-1950s — the period of the Khrushchev Thaw. But even during that period Soviet authorities tried to restrict departure of Soviet people to Finland to meet their relatives and visit their native places worrying they might stay in Finland for permanent residence. 1960s — 1980s became a period of mutual beneficial economic relations between the USSR and Finland. The most vivid example of that cross-border cooperation was foundation of Kostomuksha city and construction of ore-dressing and processing enterprise on the territory of Karelia. Cross-border contacts between Soviet and Finish citizens during the Cold War were also carried out through the “Finland — the Soviet Union” community by the tourist exchange and development of twin-city relations.