The fast-food giant is the latest company to implement a face-covering requirement, which comes amid a surge in fresh cases of the novel coronavirus across the South and West parts of the country.
"The latest science suggests droplets have the potential to stay in the air for extended periods of time, increasing the risk of virus spread, especially from asymptomatic carriers," McDonald's said in a news release. "As a result, the most recent guidance from the Centers for Disease Control (CDC) reiterates face coverings are an effective way to prevent the spread of COVID-19."
To date, nearly 82 percent of its restaurants are in states or localities that require facial coverings for employees and customers.
"It’s important we protect the safety of all employees and customers," the company added.
If a customer refuses to cover up, the company will "put in place additional procedures to take care of them in a friendly, expedited way," McDonald's said.
The policy builds on the dozens of safety procedures and protocols McDonald's has put in place throughout its restaurants since the outbreak, according to the fast-food chain.
The announcement comes just after a slate of restaurants and major retailers, from Starbucks to Home Depot, issued similar mandates in recent weeks in response to the progression of the pandemic.
As of July 24, the number of confirmed cases of the novel coronavirus in the U.S. has surpassed 4 million, according to data from Johns Hopkins University.