What was the worst decision in boxing history?

In ALL of boxing, Roy Jones Jr vs South Korean fighter Park Si-Hun.

RJJ lost a 3–2 decision despite pummeling Park for three rounds, landing 86 punches to Park's 32. Allegedly, Park himself apologized to Jones afterward and the referee told Jones that he was dumbstruck by the judges decision.One judge shortly thereafter admitted the decision was a mistake and all three judges voting against Jones were eventually suspended. An official IOC investigation ending in 1997 found that three of the judges had been wined and dined by South Korean officials. The incident led Olympic organizers to establish a new scoring system for Olympic boxing.

Manny Pacquiao vs Mayweather

Alfredo Escelara vs Tyrone Everett in Philadelphia is one of the worst decsions to ever happen in the history of boxing. Shortly thereafter Tyrone was shot and killed by his girlfriend. This was in 1976 I believe.

Lewis vs. Holyfield 1

Mike Tyson deciding to bite Holyfields ears off

Rjj olympics , whitaker chavez , but tyson cave vs escandon is by far worst ive seen live.

I seen a few robberies but Williams-Lara is a big robbery. Williams clearly loss that fight and he know it. I think the judges were fired after that.

Pac vs. Bradley 1 is another one.

i've seen a few rounds awarded to the wrong person and often seen the reining champ called the winner when he really didn't win

A bad one is DLH vs Trinidad

Unfortunately there's been too many for me to be able to single one out.