First recorded by Bo Diddley (1955).
Inspired by “Hoochie Coochie Man” by Muddy Waters (1954).
Popular versions by the Yardbirds (1964), the Yardbirds (1965).
From the wiki: “‘I’m a Man’ is a rhythm and blues song written and recorded by Bo Diddley in 1955 (credited to ‘E[llas] Daniels’, Bo Diddley’s birth name), and was one of the first songs Diddley recorded for Checker Records.
“Unlike his self-titled ‘Bo Diddley’, recorded the same day (March 2, 1955 in Chicago), ‘I’m a Man’ does not use the ‘Bo Diddley beat’. Rather, it was inspired by Muddy Waters’ 1954 song ‘Hoochie Coochie Man’, written by Willie Dixon. After Bo Diddley’s release, Waters recorded an ‘answer song’ to ‘I’m a Man’, in May 1955, titled ‘Mannish Boy’, a play on words on Bo Diddley’s younger age as it related to the primary theme of the song.
“In a Rolling Stone magazine interview, Bo Diddley recounts that the song took a long time to record because of confusion regarding the timing of the ‘M … A … N’ vocal chorus.