The Mali international moves to Loftus Road from French club Nancy, and expressed his delight at his long-term switch to England.
“It’s a dream come true to sign this contract,” he told the club’s official website.
“I loved my time here on loan and I couldn’t be happier to join QPR on a permanent deal.
“It’s a fantastic club to play for and the owners have great plans for the future – I am just delighted to be part of it,” he beamed.
Mark Hughes is also glad to have tied up a permanent deal for Diakite, and feels that the player will be important for Rangers in 2012-13.
“He’s a very accomplished footballer and he’s made to measure for the Premier League.
“He’s got good pace, strength and ability on the ball and he’s going to be a great asset for us going forward. There’s still so much more to come from him.”
By Gareth McKnight