Flavio Oscar Cianciarulo (born July 26, 1964), a.k.a. Sr. Flavio, is the electric and upright bass player from the reunited Argentine band Los Fabulosos Cadillacs and Latin American supergroup De La Tierra.

Sr. Flavio has been the bass player from the beginning of the band when they were called Cadillac 57. He also sang many of the songs, and was one of the main songwriters of the band along with singer Vicentico.