The defenders have both signed four-year deals at the Stadium of Light with their chances of first-team football under Jose Mourinho having diminished at Old Trafford.
Sunderland has completed the signings of Manchester United pair Paddy McNair and Donald Love for a combined fee of 5.5 million pounds ($7.13M).
The defensive duo have signed four-year contracts at the Stadium of Light to reunite with former United boss David Moyes, who succeeded Sam Allardyce as manager in July.
"Sunderland AFC have completed the double signing of Paddy McNair and Donald Love from Manchester United for a fee of £5.