State Counselor Aleksandr Davydov [ru] was appointed "diplomatic agent and consul general in Bulgaria" on 13 September [O.S.

[6] Diplomatic relations were again suspended on 6 October 1915, after Bulgaria's entry into the First World War on the side of the Central Powers.

After the withdrawal of Russia from the war and the signing of the Treaty of Brest-Litovsk on 3 March 1918, diplomatic relations were nominally restored between the Russian government, now under Bolshevik leadership, and the Central Powers.

[6] On 5 September 1944, with the Red Army advancing towards the Balkans, the Soviet Union declared war on Bulgaria.

Relations between the Soviet Union and Bulgaria were restored in August 1945, and on 6 January 1946 an agreement was reached to upgrade the diplomatic missions into embassies.