He defeated Canadian Dale Brown in a controversial but unanimous decision on May 20, 2005, on Friday Night Fights to capture the vacant IBF title.
He unified the title by beating Frenchman Jean-Marc Mormeck on January 7, 2006, for his WBA and WBC belts, making Bell the second undisputed champion of the division, with Evander Holyfield being the first.
[1] The IBF later stripped Bell in April 2006 for pulling out of a mandatory bout against Steve Cunningham because of a tooth problem.
After nearly 11 months of inactivity, Bell was due to take part in the postponed Superfighter Tournament at heavyweight on December 1 of that year.
Bell lost the WBA, WBC and lineal cruiserweight titles to Jean-Marc Mormeck on March 17, 2007 in the Frenchman's backyard in Levallois, France via a close but unanimous decision.