"I'm a Man" is a popular American song written and released by Bo Diddley in April 1955 on Checker Records as the b-side to his hit "Bo Diddley". The writing credit is under Diddley's real name, Ellas McDaniel. Based on Muddy Waters' 1954 blues song "Hoochie Coochie Man" written by Willie Dixon, Waters recorded a cover of "I'm a Man" in May 1955, retitled "Mannish Boy", a play on words on Bo Diddley's younger age as it related to the primary theme of the song. The song is ranked #369 on the Rolling Stone magazine's list of The 500 Greatest Songs of All Time. The song, as well as the A-side, reached #1 on Billboard's R&B Singles chart.
The song was recorded on March 2, 1955 in Chicago, Illinois. Producing the session were Leonard and Phil Chess, and Bo Diddley, and backing Diddley (vocals), guitar) were Billy Boy Arnold (harmonica), Otis Spann (piano), Jerome Green (maracas), Willie Dixon (bass), and either Frank Kirkland or Clifton James (drums). According to Bo Diddley, in a Rolling Stone magazine interview, the song was took a long time to record because he couldn't spell out man slowly enough.
The song has been covered often by blues and rock musicians, most famously by The Yardbirds. It was released as single and later included on the 1965 U.S. compilation album, Having a Rave Up. The Yardbirds' version (with "Still I'm Sad" as its b-side, released by Epic in the U.S.) peaked at #17 on the Billboard Hot 100 in 1965. The Yardbird's version is also noted for the rhythm change, when the beat speeds up, featuring some unusual percussion making clacking sounds, until it ends in a climax. The Royal Guardsmen also recorded the song, as well as Doug Sahm, who performed the song in a San Francisco, California nightclub, in the film, More American Graffiti.
The Who recorded the song for their debut album My Generation (1965). The Japanese psychedelic band The Beavers covered the song in the late 1960s, as did the Yellow Payges. Tom Petty & the Heartbreakers covered this song throughout their 2006 North American "Highway Companion" tour. A version from this tour was later featured on The Live Anthology set.
George Thorogood's song "Bad to the Bone" (for which Diddley appeared in the music video) and AC/DC's "Whole Lotta Rosie" also borrow from the guitar riff, vocal melody, and overall structure of "I'm a Man".