The Brazilian full-back will spend next season at Loftus Road.
Fabio has struggled to get regular first-team football at Old Trafford as he is currently behind Patrice Evra in the pecking order.
QPR boss Mark Hughes told the club’s official website: “It’s a great opportunity for us to loan a good, young player, who has decent experience of playing for a top Club like Manchester United.
“He’s played a lot of senior games for United, so it shows the quality he’s got.
“I know they think very highly of him and we believe he has all the attributes to be a success here next season.”
He added: “First and foremost, he’s a good defender. He’s got great enthusiasm as well, and just like his brother (fellow United team-mate, Rafael), he’s a top professional.
“We can give him the games he’s craving at this stage of his career, so it benefits everybody.
“He’s very versatile – he can play left or right-back and he’s also been utilised in midfield by Sir Alex (Ferguson) in the past, so we know what we’re getting, and that’s a very good player.”
Fabio said: “I’m so happy to be here.
“This loan is so important for me in terms of my career. I want to play as many games as possible here. I want to play well and win games as well.
“It’s a good move for my career and for my confidence.
“Sir Alex Ferguson said that I’d enjoy it here and told me to play as many games as I can.”
He added: “I know that QPR is a Club with great history. I read about the history and that’s why I’m here.
“I also came here because I’m ambitious. I want to help QPR progress up the Premier League.
“Hopefully the fans will enjoy watching me in action, because I’ll do my best.”
