However, without a win since, Warnock's side slipped towards the relegation zone and needed a last-minute equaliser from Heidar Helguson to avoid an FA Cup third-round defeat by League One side MK Dons on Saturday.
QPR's Malaysian owner and chairman Tony Fernandes said: "This decision has been made in the best interests of the club and I can assure everyone that this is not a decision that was made lightly.
Ian DennisBBC Radio 5 live senior football reporter
With just one win in their last 12 games the QPR board felt it was time for a change. Warnock took Rangers into the Premier League for the first time in 15 years but obviously the board doubted his ability to retain their top-flight status.
It's highly likely to be Mark Hughes who'll be offered the chance to keep QPR in the Premier League. As everybody knows, QPR have money to strengthen and it's interesting they've already targeted two players who've played under Hughes in Andrew Johnson and Chris Samba.
"Sadly, our recent run of poor form has seen us slip alarmingly down the table and the board felt it was the right time to make a change.
"Neil has acted with honesty, professionalism and integrity throughout his time at the club, and I would personally like to thank him for his significant contribution to QPR over the last 22 months."
Warnock, who left Crystal Palace to take charge of Rangers, added: "Obviously I'm very disappointed, but having achieved so much, I leave the club with a great sense of pride.
"The board at QPR are hugely ambitious and I wish them every success for the future."
Warnock, one of only 19 bosses to have taken charge of 1,000 domestic matches in England, began his managerial career at Gainsborough Trinity before leading Scarborough to the Football League and winning successive promotions with Notts County.
Promotions with Huddersfield and Plymouth were followed by spells in charge of Oldham and Bury, with Warnock taking control at hometown club Sheffield United in December 1999.
He led the Blades to semi-finals in the both the FA and League Cups and, after a play-off final defeat, promotion to the Premier League in 2006.
NEIL WARNOCK FACTFILE
1948: Born 1 December, in Sheffield
1967: Begins playing career at Chesterfield aged 19
1981: First full-time managerial job with Northern Premier League side Gainsborough Trinity
1987: Leads non-league Scarborough into Football League
1993: Guides Huddersfield to Autoglass Trophy final at Wembley in his first season
1999: Appointed Sheffield United boss after spells with Notts County, Plymouth, Oldham and Bury
2003: Reaches FA Cup and League Cup semi-finals with the Blades
2006: Manages in top-flight for the first-time after the Blades win promotion
May 2007: Leaves Bramall Lane after controversial Premier League relegation at the expense of West Ham
October 2007: Joins cash-strapped Crystal Palace
March 2010: With Palace in administration, Warnock crosses London to take over QPR
May 2011: Takes the Hoops into the Premier League
February 2012: Leaves Loftus Road with QPR sitting 17th in the Premier League.
United spent only one season in the top flight before being relegated, a campaign ultimately marred by
the Carlos Tevez affair,
and Warnock resigned in May 2007, arriving at Palace four months later.
The former Chesterfield and Rotherham player said he would retire at the age of 60 before changing his mind and has also previously suggested that the Rangers role would be his last in management.
Warnock added: "I have enjoyed my time here more than anywhere else and the QPR fans have been brilliant with me - they deserve success.
"My biggest regret is that the takeover didn't happen earlier, because that would have given me the opportunity to bring in the targets I'd pinpointed all last summer and probably given us a better chance to succeed in the Premier League.
"I've been involved in the game a long time and I will be spending the immediate future with my family and friends before deciding my next career move."
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