Unfortunately there is no undisputed heavyweight champion.
The current heavy weight champion of boxing is Vladimir Klitschlow. He is from the Ukraine and weighs 243 pounds, or 220 kilograms.
vladimir klitschko vladimir klitschko
From April 5, 1915 to July 4, 1919 - Heavy weight boxing champion - Jess Willard ( American )
Chris Archiballs. Great fighter from the mean streets.
Wasn't Wladimir in as champion at that point(?)