The teams have agreed to meet at Perth’s 60,000-seater Optus Stadium as part of an Australian tour planned by Leeds before the start of the 2019-20 campaign.
The meeting with the Old Trafford side will take place on Wednesday, July 17, the first encounter between two old and bitter adversaries for almost eight years.
Manchester United ran out 3-0 winners at Elland Road during their most recent clash in September 2011, a League Cup third-round tie.
Eighteen months earlier, a goal from Jermaine Beckford handed Leeds a memorable 1-0 FA Cup win at Old Trafford at a time when the Yorkshire club were fighting to escape from League One.
Leeds are preparing to announce further fixtures for the trip to Australia and reports over the weekend said they would play A-League outfit Western Sydney Wanderers four days after their friendly against Manchester United.
The friendlies will form part of an extended training camp at an advanced stage of pre-season, setting Leeds up for their centenary year.
Angus Kinnear, Leeds’ managing director, said: “A lot of hard work behind the scenes has gone into making this possible and I’m sure it will be a great success.
“The trip, including the game against long-standing rivals Manchester United and some more fixtures to be announced, will be a fantastic part of our centenary season and is expected to attract thousands of visitors.”
Kinnear said he hoped up to 5,000 Leeds fans would make the trip for the club’s first ever appearance down under. Tickets will go on sale to season-ticket holders and members on November 27 before being made available to fans registered for pre-sales on November 28. General admission tickets will be available from November 29, with prices starting from £40.