Aldo, who was the undisputed featherweight king for nearly a decade, leaves the sport with a professional record of 28-7. He is widely considered one of the greatest featherweights of all time, and his resume includes wins over some of the biggest names in the sport, including Urijah Faber, Chad Mendes, Frankie Edgar, and Jeremy Stephens.Aldo’s retirement comes just one month after his last fight, a loss to Petr Yan for the UFC featherweight title. Aldo had been on a tear leading up to that fight, winning five in a row, but was ultimately unable to dethrone the new champion.”It was a tough decision, but I’m retiring,” Aldo told ESPN. “I no longer have the burning desire to fight. I’m not motivated to keep training and competing at the highest level. I’m not motivated to put in all the hard work required to be a champion.”I’m thankful for everything the UFC has done for me, and I’m proud to have been a part of this sport for so many years. I’m leaving the sport with my head held high and I’ll always cherish the memories I have of competing in the Octagon.”Aldo added that he plans to stay involved in the sport in some capacity, but did not elaborate on what that might entail.”I’ll still be involved in the sport, but in a different way,” he said. “I’m not closing the door on anything, but for now, I’m just going to enjoy my life and my family.”Aldo’s retirement ends one of the most decorated careers in MMA history. He was a multi-time champion in both the UFC and WEC, and his resume includes some of the biggest names in the sport. He will surely go down as one of the all-time greats, and his retirement is a sad day for the sport of MMA.