"If You Don't Know Me by Now" is a song written by Kenny Gamble and Leon Huff and recorded by the Philly soul musical group Harold Melvin & the Blue Notes, which became their first hit after being released as a single in 1972 topping the US R&B chart and peaking at number three on the US Pop chart. Patti LaBelle later made the song as part of her concert repertoire in 1982. A live version appears on her 1985 album, Patti. Rod Stewart also included this song on his 2009 album Soulbook.