Magic Slim, a contemporary of blues greats Muddy Waters and Howlin' Wolf who helped shape the sound of Chicago's electric blues, has died aged 75.
His manager Marty Salzman says Slim died shortly after midnight on Thursday at a Philadelphia hospital.
He said Slim had health problems that worsened while he was on tour several weeks ago in Pennsylvania.
Magic Slim and the Teardrops performed Chicago-style electric blues, led by his singing and guitar playing, and were regulars on the music festival circuit.
Slim, born Morris Holt in Mississippi, established himself in Chicago's thriving blues community in the 1950s but more recently lived in Lincoln, Nebraska.
Mr Salzman called Slim "the real deal" with fans around the globe.