All of United's players - barring those currently out on loan - are eligible to play for the Reds in the Premier League this season.
Sir Alex Ferguson, and his fellow top-flight manager's had until 17:00 BST on Wednesday 1 September to submit a squad of a maximum of 25 players* to the Premier League.
There had been some media debate as to whether Hargreaves, still currently receiving treatment in the US for a tendonitis problem that his limited him to one substitute appearance since September 2008, would make the final squad. But he has been included.
United's Champions League squad has also been submitted to UEFA, European football's governing body, and now has to be verified before being confirmed.
*Premier League rules state that each club must submit a squad, maximum 25 players, containing eight home-grown players (players trained in England or Wales for 36 months before the age of 21), with an additional unlimited number of players aged 21 or under on 1 January that year.
MANCHESTER UNITED (23)
Keepers: Edwin van der Sar, Tomasz Kuszczak.
Defenders: Gary Neville, Patrice Evra, Rio Ferdinand, Wes Brown, Nemanja Vidic, John O'Shea, Jonny Evans.
Midfielders: Owen Hargreaves, Anderson, Ji-Sung Park, Michael Carrick, Nani, Darren Fletcher, Antonio Valencia, Darron Gibson, Paul Scholes, Ryan Giggs.
Strikers: Michael Owen, Dimitar Berbatov, Wayne Rooney, Javier Hernandez.
Squad cost: £200m
(United can also use young players including: Ben Amos, Fabio, Rafael, Ritchie De Laet, Gabriel Obertan, Bebe, Chris Smalling, Federico Macheda.)