A town in WA's South West has udderly smashed the Guinness World Record for the largest gathering of people dressed as cows.

The record was previously held by the town of Fairfax in Virginia, USA, where 470 people dressed as cows last year.

On Saturday a total of 1,352 people dressed in cow onesies to break the record at Cowaramup's Deja-Moo Country Fair.

The fair was held on the second anniversary of 32 cow statues being installed in the town's main street.

Jill Turton, from the Cowaramup Retailers Association, said the cows had helped with the branding of the town, long referred to by locals as "Cow-Town" in a nod to the region's dairy industry.

"We've become a minor destination in a way," she said.

"People love our cows, they come and stop, have their photos taken and while they're here they go and visit all the shops."

She said retailers had worked on developing the cow theme to brand the town.

"This idea has just worked perfectly for us so it's certainly worked to build the brand and build the recognition of our town," she said.

Cowaramup residents Zephyr Morris, Ella Turton, Ella Sibly, Gary Miller, Brandie Kenna and Wendy Sibly preparing for the world record attempt. ( Supplied: Jill Turton )

"People regularly stop along the road and have their photos taken with cows.

"We've seen some really interesting developments with people trying to have funny pictures taken with our cows."

You could say they have now milked the theme for all it is worth.

Marie Counsel travelled from the Perth suburb of Mount Lawley to join the world record attempt, along with her husband, sister and 28-year-old daughter Lauren.

"It was in fact my daughter who came across the website and said, 'Wouldn't it be cool to do it?'" she said.

"We thought it would be a lovely thing to go down and get involved.

"Mind you, I never thought we'd get my husband into a cow onesie!"