The Leeds-based retail giant challenged an Employment Appeal Tribunal decision that jobs in Asda stores are comparable with those in the firm's distribution centres.
Giving judgement at the Court of Appeal in London earlier today, senior judges dismissed Asda's appeal and ruled in favour of thousands of retail workers, mostly women, who argue they should be paid the same as those working in the supermarket's depots.
Lord Justice Underhill, sitting with Lord Justice Peter Jackson and Lord Sales, ruled that for both retail workers and distribution workers "Asda applied common terms and conditions wherever they work".
The judge added that Asda's application to appeal to the Supreme Court had been refused.
Following the hearing, a statement issued by Asda stated: “We are obviously disappointed with the decision, which relates to a preliminary issue of whether jobs in different parts of the business can be compared.
"Asda brought this appeal because it involved complex legal issues which have never been fully tested in the private sector and we will continue to ensure this case is given the legal scrutiny it deserves.
“We remain confident in our case. This appeal has caused no delay to the main case, which has been continuing in the Employment Tribunal.
"The Tribunal has yet to consider whether the jobs are of equal value in terms of their demands; it is only if some jobs are of equal value that the tribunal will go on to consider the reasons for the pay differential between them, including the fact that there are different market rates in different industry sectors."
The statement added: “At Asda, our hourly rates of pay in stores are the same for female and male colleagues and this is equally true in our depots. Pay rates in stores differ from pay rates in distribution centres because the demands of the jobs in stores and the jobs in distribution centres are very different; they operate in different market sectors and we pay the market rate in those sectors regardless of gender.”