On 28 December 1922 , a conference of plenipotentiary delegations from the Russian SFSR , the Transcaucasian SFSR , the Ukrainian SSR and the Byelorussian SSR approved the Treaty of Creation of the USSR and the Declaration of the Creation of the USSR , forming the Union of Soviet Socialist Republics .
On 28 December 1922 , people from the Russian SFSR , the Transcaucasian SFSR , the Ukrainian SSR and the Byelorussian SSR approved the Treaty of Creation of the USSR and the Declaration of the Creation of the USSR , creating the Union of Soviet Socialist Republics .