The Soviet-Finnish Treaty of Friendship, Cooperation and Mutual Assistance which was concluded on 6 April 1948 completed the post-war settlement between Moscow and Helsinki. At the same time, it was one of the foundations of stability in northern Europe and it directly affected the interests of Sweden, whose neutral status remained in doubt aft er WWII. Stockholm paid close attention to foreign policy developments in its Nordic neighbours, including Finland, which chose to establish good neighbourly relations with the Soviet Union aft er the 1944 Moscow armistice. Moscow assumed that Sweden might be wary of the Soviet-Finnish mutual assistance treaty and shift its foreign policy line somewhat towards the West. This study is of interest due to the lack of a detailed analysis of the Swedish position on the conclusion of the Soviet-Finnish Treaty in historiography. The author uses sources from Swedish and Russian archives and libraries. The basis of source study was formed by the documents kept in the National Archives of Sweden (Riksarkivet) in Stockholm. Particular attention was paid to the collections of the Foreign Policy Department (Utrikesdepartementets arkiv), which contain reports from the Swedish embassies to Finland and the Soviet Union. The research mainly involved internal correspondence between the Swedish Ministry for Foreign Affairs and its representatives in these countries. The author refers to the minutes of the meetings of the Swedish Riksdag (Riksdagens protokoll) which allow to determine the position of the Swedish political circles concerning the conclusion of the Soviet-Finnish Treaty. A separate group of sources consists of the leading Swedish periodicals. The very important diaries of Finnish President J.K. Paasikivi shed light on the Soviet-Finnish negotiations during the period in question and analyse the details of Swedish-Finnish relations.