The contest is held in Petaluma, California, each year as part of the Sonoma-Marin Fair and has attracted a huge amount of media attention.
First established in the 1970s, organisers say it is held to “celebrate the imperfections that make all dogs special and unique”.
It now attracts audiences of up to 30,000 people, with the winner receiving $1,600, a trophy and a free trip to New York City.
In the 2022 edition Mr Happy, a 17-year-old Chinese Crested-Chihuahua mix from Arizona, took home the prize.
And there have been plenty so-ugly-they-are-adorable entries over the years.
Here are 19 of the dogs with faces only a mother could love.
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It now attracts audiences of up to 30,000 people, with the winner receiving $1,600, a trophy and a free trip to New York City.
![Chu sticks his head between bars before competing in the World's Ugliest Dog Competition in 2015.](https://www.scotsman.com/webimg/b25lY21zOjFlNzRlMmY4LTllMWQtNGY2NC1iZGIxLWRhN2UyNTQ3Mjc3ODowYzNmYzQ5OC0wZDNkLTRjYTYtYTNlYS0xZmZjNjMzOWIxNDU=.jpg?crop=3:2&width=800)
5. Chu
Chu sticks his head between bars before competing in the World's Ugliest Dog Competition in 2015. Photo: JOSH EDELSON
![Contest judges inspect Gus, a one-eyed, three legged Chinese Crested dog that was named the winner of the 20th Annual World's Ugliest Dog Competition 2008.](https://www.scotsman.com/webimg/b25lY21zOjFkZjRiMzhlLTI0MzYtNGRiMi04NWQwLWExMjUyMGU5YmI0ZjpiYjgwNDgyMy1lZTFiLTQ0YzktODI0OS01NTE5YWY2OGY3NWE=.jpg?crop=3:2&width=800)
6. Gus
Contest judges inspect Gus, a one-eyed, three legged Chinese Crested dog that was named the winner of the 20th Annual World's Ugliest Dog Competition 2008. Photo: Justin Sullivan
![A Japanese Crested dog, Pee Wee Martini is held by its owner Kristin Maszkiewicz at the 2007 World's Ugliest Dog Contest.](https://www.scotsman.com/webimg/b25lY21zOmY1NzE4NTlhLTFiZmItNDlmOS04Y2Q0LTNiMWUyM2ZiYmRmZjoxNTI3MmEzZS01NTc0LTQ4NjMtYTk1OS0xZGViOWUzMGJjYTg=.jpg?crop=3:2&width=800)
7. Pee Wee Martini
A Japanese Crested dog, Pee Wee Martini is held by its owner Kristin Maszkiewicz at the 2007 World's Ugliest Dog Contest. Photo: David Paul Morris
![Poppy gets a kiss from her owner Tamara at the 2007 World's Ugliest Dog Contest. Poppy was rescued, like many dogs in the contest and was saved from a puppy mill by Crest-Care one of many animal rescue organizations found across the country.](https://www.scotsman.com/webimg/b25lY21zOjQyODlmOTg3LTg4M2ItNGM2Zi05ZmYyLTNmNGNjZGY1M2ZlNDo0N2RmNDQ1NS05YTNlLTRjY2QtOTdiNi05MWU2M2Q2MTM1OWE=.jpg?crop=3:2&width=800)
8. Poppy
Poppy gets a kiss from her owner Tamara at the 2007 World's Ugliest Dog Contest. Poppy was rescued, like many dogs in the contest and was saved from a puppy mill by Crest-Care one of many animal rescue organizations found across the country. Photo: David Paul Morris