The Independent Workers Union of Great Britain (IWGB) had sought to argue that riders were workers so that they could claim union recognition.
"We welcome the decision of the Committee".
Dan Warne, the managing director for Deliveroo in the United Kingdom and Ireland, said: "This is a victory for all riders who have continuously told us that flexibility is what they value most about working with Deliveroo".
IWGB said in a statement that it was reviewing the judgment with its lawyers and would decide the best course of action. This would also have afforded them certain rights, such as to the minimum wage and holiday and sick pay.
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The company said its turquoise-and-grey clad "Roomen" and "Roowomen" wanted to keep flexibility of being self-employed. 85 percent of you tell us that flexibility is why you work with Deliveroo and that is why today's decision is so important.
Deliveroo refused and the case was taken to the CAC.
IWGB General Secretary Dr Jason Moyer-Lee said: "It seems that after a series of defeats, finally a so-called gig economy company has found a way to game the system".
"We find that the substitution right to be genuine, in the sense that Deliveroo have decided in [its new contract] that riders have a right to substitute themselves both before and after they have accepted a particular job".
Crowley Woodford, employment partner at law firm Ashurst said: "This will be a significant blow to the unions who are trying to expand their membership within the gig economy by challenging the basis on which such employers engage and use their labour".