The deal will include the launch of a co-branded website offering betting, poker and casino games, which will be promoted on the club's TV station, MUTV. Betfred will also provide in-stadium betting exchanges.
The partnership comes several months after Manchester United declined a shirt sponsorship deal with rival gaming site Mansion.
Online gaming sites have taken the sports sponsorship market by storm over the past year, with Mansion agreeing a record £34m shirt sponsorship deal with Tottenham Hotspur. Aston Villa also recently signed a shirt sponsorship deal with online gaming company, 32Red.
Last week Sportech became the official gaming partner of fellow Premiership side Everton. The deal includes a gaming section on the club's website. Sportech will use the deal to promote online games, such as bingo, poker and casino.