The company discovered the data breach after hiring consultants to "investigate unauthorised activity on an internal security system," the Wall Street Journal reported, quoting McDonald's.
In the US, the breach disclosed some business contact information for employees and franchisees, along with some information about restaurants.
The "attackers stole customer emails, phone numbers and addresses for delivery in South Korea and Taiwan".
In Taiwan, hackers also stole employee information including names and contact information.
The breach didn't include customer payment information, according to McDonald's.
McDonald's said on Friday that its business operations were not interrupted by the data breach and "in the coming days, a few additional markets will take steps to address files that contained employee personal data."
Not just McDonald's, another fast-food chain Domino's suffered a data breach in India when a hacker made 13TB data of nearly 18 crore orders of Domino's India with key details public on the Dark Web earlier this month.
According to independent cyber security researcher, Rajshekhar Rajaharia, data of 18 crore orders from Domino's Pizza in India has now become public, that contains name, email, phone number and even the GPS location of the users.
In a statement, Jubilant Foodworks that owns the master franchise for Domino's Pizza in India, had said that the company experienced an information security incident recently.
"No data pertaining to financial information of any person was accessed and the incident has not resulted in any operational or business impact," the spokesperson had said.