According to Aguilera and the production team, Back to Basics draws influences from 1920s–1940s jazz and soul music. However, music critics identified the record as a pop, and R&B album with similarities to 1960s, 1970s and 1980s albums. Dorian Lyskey writing for The Guardian thought that the album's concept "is so wide as to be meaningless", while Serene Dominic from Phoenix New Times compared Back to Basics' musical style to rock band The Beatles' self-titled album (1968).
