Nat Riddles (4 February 1952 - 11 August 1991) was a blues harmonica player who played an important role in the New York blues scene during the late 1970s to mid-1980s. Born in Bronxville, a Westchester County suburb of New York, he was educated at Brooklyn College and the Pratt Institute. In the early 1980s, he became known in New York blues circles for his street performances with guitarist Charlie Hilbert as part of a free-form duo that he labeled 'El Cafe Street.'
Riddles performed with Larry Johnson and Odetta as well as Hilbert. He recorded several albums with Johnson (one produced by Len Kunstadt for Spivey Records, one produced by Horst Lippmann) and a solo album on Spivey entitled The Artistry of Nat Riddles. He also contributed several cuts to a Spivey series of LPs entitled New York Really has The Blues.
Riddles died of leukemia in August 1991 in Richmond, Virginia at the age of 39.
In 2007 the Modern Blues Harmonica record label issued a compilation album of Riddles, entitled El Cafe Street Live!