"If You Don't Know Me by Now" is a song written by Kenny Gamble and Leon Huff and recorded by the Philadelphia soul musical group Harold Melvin & the Blue Notes, which became their first hit after being released as a single in 1972, topping the R&B chart and peaking at number three on the Pop chart. It was covered by Simply Red in 1988, and became a wordwide hit reaching number one on the US Hot 100 on July 15, 1989 and peaking at number two in the UK Singles Chart. It also topped the ...