• Pets - which must have ugliness certified by a vet - will compete this Friday
  • Competition held every year since 1998 in Sonoma-Marin Fair, California
  • Organisers say it's 'not about making fun of ugly dogs'
These pets may all be pug-ugly - but only one will hound out the competition to be crowned the ugliest dog in all the world.

The rough-looking animals - all of whom have been certified 'naturally ugly' by their vets - will fight it out in California to receive the dubious honour of first place at the World's Ugliest Dog Contest.

Judges will decide this Friday which of the animals - with their toothy smiles, crazed hair and wild expressions - is the most displeasing of all, netting the proud owners a $1,500 prize.
Scroll down for video of last year's winner
Looking ruff: Peanut, pictured, is one of the ugly contestants hoping to come out top dog on Friday
Looking ruff: Peanut, pictured, is one of the ugly contestants hoping to come out top dog on Friday
Blinky: Perhaps Willie Bean Walker, pictured, will excel in the 'unique features' category
Blinky: Perhaps Willie Bean Walker, pictured, will excel in the 'unique features' category
However, organisers insist the event is 'not about making fun of ugly dogs' - but a fun way to showcase beloved pets who don't meet traditional standards of beauty.
 
The contest, now in its 26th year, is held annually at the Sonoma-Marin Fair in California.
Contestants are judged in four main categories - first impressions, unique features, personality and audience reaction. 
Wild hair: The contest has taken place in California for 26 years. Pictured is Sweetpee Rambo
Not impressed: The dog which takes home the dubious honour of being the ugliest will win its owner $1,500. Pictured is Cyndy Loo Whoo
Wild hair: Personality and audience reaction also factor into the judgements. Pictured are Sweetpee Rambo, left, and Cyndy Loo Whoo, right
A spokesman for the event said: 'Beauty is in the eye of the beholder and the contest has been a testament that all dogs do not have to meet pedigree standards to be man's best friend.
'The owners of all kinds of dogs are also all kinds of people - from youngsters to senior citizens, each proud of their pet despite missing fur, being crossed eyes, waddling like a duck or having mismatched ears. 
'The World's Ugliest Dog Contest is not about making fun of ugly dogs but having fun with some wonderful characters and showing the world that these dogs are much loved and beautiful creatures.
'The winning dog becomes an instant celebrity with international attention. 
'The owner can expect to be invited on national television shows and to be guests at all kinds of events, bringing attention to loving and rescuing dogs who are not always the first chosen.'
Hungry: Dogs like Rue, pictured, will be hoping for the celebrity status an Ugliest Dog win can bring
Chasing fame: Dogs like Boogie, pictured, won't let their lack of a full coat of fur stand in their way
Chasing fame: Apparently international celebrity awaits the winners of the contest, which could include Rue, left, or Boogie, right
Heartwarming: Contest organisers emphasised that the owners all loved their pets regardless of their unusual features
Heartwarming: Contest organisers emphasised that the owners all loved their pets regardless of their unusual features
Wild: Many of the dogs have been rescued and adopted from shelters
Not quite Lassy: This dog's owners clearly had a sense of humour, naming him Quasimodo
Sense of humour: The owners clearly enter their pets to the competition lightheartedly, as shown by names for their dogs such as Rascal, left, and Quasimodo, right