According to the Back in the USSR Songfacts, this was inspired by the The Beach Boys song, California Girls. During the recording session on 22 August 1968, Ringo Starr walked out and announced that he had quit. "Back in the U.S.S.R." was recorded without Starr, with McCartney primarily responsible for the drum parts. McCartney's drums are most prominent in the mix, but both Lennon and Harrison recorded drum tracks for the song; these are audible in the left channel of the stereo mix. Read more on Last.fm.