A jury ruled that the store had violated the Americans with Disabilities Act by dismissing the woman.
Walmart has been ordered to pay out $125 million after firing an employee with Down's Syndrome.
Marlo Spaeth had been employed by the company for 16 years but was fired from her position for issues relating to her work schedule.
She was represented in court by the US Equal Employment Opportunity Commission (EEOC), which presented three claims of disability discrimination against the store.
It argued that Spaeth had been caused "significant difficult" after her usually consistent timetable was changed, and that Walmart had not allowed her to go back to her previous work schedule.
Spaeth was fired as a result of the disagreement. When she then asked to be rehired, her request was denied.
After a four-day hearing in Green Bay, Wisconsin, a federal jury ruled that the store had violated the Americans with Disabilities Act by firing Spaeth.
However, the company have said that it expects the $125 million payout to be significantly reduced down to around $300,000, which is the maximum amount allowed under federal law.
Walmart spokesperson Randy Hargrove told
Bloomberg Law: "We do not tolerate discrimination of any kind, and we routinely accommodate thousands of associates every year.
"We often adjust associate schedules to meet our customers' expectations and while Ms Spaeth's schedule was adjusted, it remained within the times she indicated she was available.
"We're sensitive to this situation and believe we could have resolved this issue with Ms Spaeth, however the EEOC's demands were unreasonable."
Walmart was taken to court last year as well over allegations of discrimination. The company paid out $20 million after
being taken to court by the EEOC over claims that it had excluded a number of female applicants from positions as grocery packers.
