"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. It became their first hit after being released as a single in September 1972, topping the US R&B chart and peaking at number 3 on the US Billboard Hot 100.
Simply Red's version of "If You Don't Know Me by Now" was a major commercial success on the charts in 1989, giving the band their second US number one (also topping the Adult Contemporary chart), and peaking at number 38 on the Hot R&B/Hip-Hop Songs chart.
This version also won the Grammy Award for the Best R&B Song of 1989. The track was also a number-one hit in Australia and New Zealand; in the latter country, it was the best-selling single of 1989.
It reached number 2 in the UK, becoming the band's second top-10 hit after the re-issue of "Holding Back the Years" in 1986, which also reached number 2.