Gus, a Chinese crested dog, had cancer. He was nine years old.
The animal was rescued from a bad home and went on to win the annual World's Ugliest Dog contest at the Sonoma-Marin Fair in northern California.
Dead: Gus, a Chinese crested canine who was voted the World's Ugliest Dog earlier this year, fell ill with cancer
Gus came from humble origins. According to the fair, his adopted family in Gulfport, Florida, rescued him after learning he was being kept in a crate inside someone's garage.
He had one leg amputated because of a skin tumor and lost an eye in a cat fight.
Gus' owner had said the prize money from the contest would be put toward the dog's radiation treatment.