The reigning UFC welterweight champion is unbeaten since April 2007, winning 12 straight fights, including nine title defences, to run his record to 25-2.
But St-Pierre's last bout was one of his toughest.
Though he retained his belt at UFC 167 in Las Vegas on Nov. 16, St-Pierre was battered by Johny Hendricks and needed a controversial split decision to remain champ.
After the fight, the 32-year Montrealer hinted at stepping away from the octagon.
With MMA fans contemplating a future without one of the sport's most popular figures, we take a look back at GSP's rise from schoolyard bullying victim to one of the most feared and respected fighters in UFC history.