(CNN) - Naomi Campbell and Iman are two of the original black supermodels.
More than two decades after they first broke through, they say the fashion world is riddled with racism.
"We're not saying they're racist we're saying it's an act of racism by not using models of color," Naomi Campbell writes.
In a sharply worded letter to the industry, they are calling out fashion's elite.
"Eyes are on an industry that season after season watches fashion houses consistently use one or no models of color," Carol White, a modeling agent, said.
Dozens of fashion's biggest names are listed based on what the Fashion Diversity Coalition calls a lack of black models on runways during the fall 2013 collections.
To be a black model in the industry is more difficult than being a white one that's for sure.
Carol White, the agent who launched Naomi Campbell's career, says the problem is nothing new. Of the 300 female models her agency represents, just 13 are black. And she says her agency represents more than most.
"We'll take models that clients want, so therefore ratio of black versus white is quite big," White said. "It's much harder work for the bookers on the table, which is why we're more discerning about the type of black girl we take because we know they have to be stunningly beautiful have an incredible body. They have to be actually perfect."
Nadja Girimata is one of the industry's freshest faces. This is her first time being booked to walk at a Temperely London fashion show. She says she didn't know that Temperley is one of the many fashion houses that Naomi's campaign has called out.
"I would love to be booked for shows and not because 'Oh, she's going to be the only black girl' because I am me," Girimata said. "For my personality, for the person, for the model I am."
Alice Temperley says last season's casting decision was based on available models.
"We had loads of different girls," Temperley said. "We always make sure that we try and mix it up. Last autumn/winter we had 5 or 6 Asian girls. Beautiful, beautiful Asian girls."