John Len Chatman (September 3, 1915 – February 24, 1988), known professionally as Memphis Slim, was an American blues pianist, singer, and composer. He led a series of bands that, reflecting the popular appeal of jump blues, included saxophones, bass, drums, and piano. A song he first cut in 1947, “Every Day I Have the Blues“, has become a blues standard, recorded by many other artists. He made over 500 recordings. He was posthumously inducted into the Blues Hall of Fame in 1989.

Memphis Slim was born John Len Chatman, in Memphis, Tennessee. For his first recordings, for Okeh Records in 1940, he used the name of his father, Peter Chatman (who sang, played piano and guitar, and operated juke joints); it is commonly believed that he did so to honor his father. He started performing under the name “Memphis Slim” later that year but continued to publish songs under the name Peter Chatman.