thumb|Flag of the Russian SFSR (right) on a 1954 stamp with the [[Flag of the Ukrainian Soviet Socialist Republic|flag of the Ukrainian SSR (left). The stamp celebrates the 300th anniversary of the reunification of Ukraine with Russia.]]
The penultimate USSR-era flag was adopted by the Russian Soviet Federative Socialist Republic (RSFSR) in 1954 and used until 1991. The flag of the Russian SFSR was a defacement of the flag of the USSR. The constitution stipulated:
The symbol of the hammer and sickle represented the working class; more specifically, the hammer represented the urban industrial workers and the sickle represented the rural and agricultural peasants. The red star represented the Communist Party and Communism. The red of the flag represented revolution in general and the Russian Revolution in particular. The blue stripe symbolized the wide Russian skies and the waters of its seas and rivers.
History
During the October Revolution in 1917, the plain red flag was used by the Bolsheviks.
The first flag of the Russian SFSR, adopted on 13 April 1918, was a flag showing the full name of the recently created Soviet republic before the then imminent Russian spelling reform. Its ratio was unspecified.
From June 1918, the flag was red with the gold Cyrillic characters РСФСР (RSFSR) in the top-left corner, in a traditional Vyaz' style of ornamental Cyrillic calligraphy.
From 1920, the characters were redesigned as described by the . However, this flag was oftentimes not used, with the 1918 flag being used until 1937.