The class-action lawsuit in Philadelphia was brought by two former Wal-Mart employees who convinced the jury that the supermarket giant forced workers to miss a total of 33 million rest breaks from 1998 to 2001 and work later hours without pay across the state of Pennsylvania.
The decision followed a similar ruling in California in December last year when Wal-Mart, the parent company of Asda, was ordered to pay US$172.3 million (£92.5 million) to workers for missed meal breaks.
Wal-Mart said it would appeal against the Pennsylvania ruling, arguing that workers at its stores in that state were owed no more than US$6.9 million (£3.7 million).
Under Wal-Mart's policy, 30-minute meal breaks are unpaid, but an employee should be paid for rest breaks. Those who work more than six hours are allowed two 15-minute breaks.