The 26-year-old has committed his future to the Loftus Road club until the summer of 2015.
"To be given the opportunity to extend my contract is fantastic for me," Mackie said. "It's a really exciting time for the club. Now we've stayed up, I think next season could be a really big one for QPR. To be a part of the long-term future of the club is an aim of mine and I'm really happy."
Mackie is now looking for manager Mark Hughes to strengthen the QPR squad ahead of next season.
"Hopefully the manager can add even more quality to the squad in the summer to supplement what we've already got," said the former Plymouth striker, who moved to QPR in May 2010.
"With the new training ground too and the passion of the owners for the club, it's an amazing time for the football club."
Mackie returned from a double leg break to score seven goals in QPR's first season back in the Premier League.
"From day one, the fans have brilliant with me - especially when I broke my leg," he added. "They carried on supporting me all the way through that.
"It meant a lot to me. Hopefully my performances since have gone a little way to paying them back for the support that they showed me."
QPR retained their top-flight status on a dramatic final day.