The 23-year-old forward will link up with another former African Player of the Year Jay-Jay Okocha at the Reebok Stadium after rejecting the overtures of Malaga and Portsmouth to sign up with Sam Allardyce.
Diouf's agent, Alexander Grouet, said: "El-Hadji was won over by what Bolton's manager had to say. And by the club's ambition. The aim to do even better than last season's 8th place finish."
