The 20-time English champions announced on Monday that terms had been finalised with the German sportswear giant after rivals Nike decided that renewing their contract did not represent good value for its shareholders.
United's partnership with Nike, which began in 2002, will come to an end after the upcoming 2014-15 season.
The club's 10-year agreement with Adidas comes as they prepare for a campaign without the prospect of UEFA Champions League football after finishing a lowly seventh last term.
A statement on the United website read: "Manchester United plc (NYSE:MANU) has reached a ten-year agreement with adidas for a global technical sponsorship and dual branded licensing deal for a minimum guarantee of GBP 750 million, subject to certain adjustments, beginning with the 2015/2016 campaign.
"For the 2014/2015 season, Nike will continue in its role of technical sponsor and trademark licensee."
