The flamboyant pundit, who is now 72, has been covering the sport for 31-years for ITV and Channel 4 but has not been retained by IMG who will take over production from the start of next year.
Form expert Jim McGrath is the only member of the existing team over 50 that will be retained with Derek Thompson, Mike Cattermole and Alastair Down also being dropped from the new coverage that will be led by Clare Balding.
"According to Channel 4, I'm being sacked after audience research," an angry McCririck told the Daily Mirror.
"Yes, I do antagonise people, as reactions to being twice in the Celebrity Big Brother house and also on Coach Trip prove.
"Clare (Balding) is a terrific choice to lead the new young team. But it's so sad Channel 4 have again gone down the path of ageism.
"(I was sacked) Without any consultation or being asked to change my presentation style, I was only told by Channel 4's head of sport, Jamie Aitchison, half an hour before their press release."
McCririck's role will now be taken up fully by Tanya Stevenson who has been working as his sidekick for the last few years.
Channel 4 defended their decision to re-jig their line-up for their new coverage, which will see them become the sole terrestrial broadcasters of racing in the UK.
"Being the new home of horseracing is a real privilege and I'm delighted to announce this carefully selected team of presenters and reporters; a mix of broadcasting heavyweights and racing experts."
"Sports fans have something to look forward to - our racing coverage will be insightful, intelligent and ground-breaking. I'm hugely excited about the future of racing on Channel 4 and greatly look forward to 2013," said Aitchison.
"I would like to thank all of the presenting team for their commitment and enthusiasm to Channel 4 and the racing coverage over the years."
The lead commentator of the new coverage will be Simon Holt supported by Richard Hoiles. Former jockey Mick Fitzgerald and Rishi Persad have been recruited from the BBC while paddock analyst Graham Cunningham has been nabbed from Racing UK and Gina Bryce from Attheraces.
Former Gold Cup winning jockey Sam Thomas will also be part of the new team while Morning Line's Nick Luck will co-present with Balding.