"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.
"If You Don't Know Me by Now" was originally written for Labelle (a trio led by Patti LaBelle) but they never recorded it. The song's composers Gamble and Huff gave it to Harold Melvin & the Blue Notes, which featured Teddy Pendergrass as lead vocalist, and the actual background vocals done by producers Gamble, Huff, Carl Helm, and Bunny Sigler. In addition to the single release, the track was included on their debut album, I Miss You.
Patti LaBelle later made the song part of her concert repertoire in 1982; a live version appears on her 1985 album, Patti.
"If You Don't Know Me by Now" has since been recorded by a number of other artists, most notably the English pop and soul band Simply Red, who took their version to number one on the Billboard Hot 100 in 1989.
The song was chosen as one of the "Songs of the Century" by the Recording Industry Association of America (RIAA).
Simply Red's version of "If You Don't Know Me by Now" was recorded for their third studio album, A New Flame (1989), and released in March 1989 by WEA and Elektra Records as the second single from the album. It was a commercial success, giving the band their second US number one and also topping the charts of Australia and New Zealand; in the latter country, it was the best-selling single of 1989. On the UK Singles Chart, it peaked at number two, becoming the band's second top-10 hit in their home country. This version won the Grammy Award for the Best R&B Song of 1989. The single's music video, filmed in London, was directed by Vaughan Arnell and Anthea Benton.
According to the producer, Stewart Levine, he did not want too much orchestration on the record, and went with a two-part harmony instead of a three-part harmony. Mick Hucknall admitted he loved Harold Melvin & the Blue Notes' version, and stated he danced to their music when he was 13.
Jerry Smith from Music Week wrote, "Top-notch purveyors of smooth soul, Simply Red deliver this excellent version of the old Harold Melvin & the Bluenotes classic, lifted from their already platinum-selling A New Flame LP. As a follow-up to their 'It's Only Love' hit, it's a sure fire winner. Expect mass exposure."