The World’s Ugliest Dog Contest is celebrating man’s best friend’s perfect imperfections.

The pooches – many of which are adoptable or previously adopted – will face off in a red carpet walk and Faux Paw Fashion Show. The contestants are judged on first impressions, unusual attributes, personality and audience reaction.

A blind Chihuahua-Chinese Crested mix named Sweepee Rambo bested 16 other homely hounds in last year’s competition and waddled away with $US1,500 ($A1,981), a trophy and a flight to New York with her owner, Jason Wurtz, for media appearances.

The then-17-year-old champion proved that third time’s the charm after falling short in the competition twice before.

By celebrating inner beauty, organisers say they hope to showcase that all dogs, regardless of physical appearance, can be lovable additions to any family.

Contest rules prevent owners from intentionally altering their animals to enhance appearance for the purpose of the contest. These pooches are celebrated for their natural ugliness, organisers say.