Giuliani said the station's ban is overly broad and "a clear violation of free speech".
Giuliani issued a statement saying he had heard of WABC Radio owner John Catsimatidis' decision through "a leak" to The New York Times. Catsimatidis confirmed his decision in a text message to The Associated Press.
Giuliani "left me no option," Catsimatidis told the Times, saying the former New York City mayor had been warned twice not to discuss "fallacies of the November 2020 election".
"And I get a text from him last night, and I get a text from him this morning that he refuses not to talk about it," the Republican businessman, who has fundraised for Donald Trump, told the newspaper.
John Catsimatidis and — Rudy W. Giuliani (@RudyGiuliani) @77WABCradio fired me for refusing to comply with their overly broad directive stating I'm, 'prohibited from engaging in conversations relating to the 2020 Presidential Election.'I'll explain more here on X and #AmericasMayorLive at 8 pm tonight... (1/4)May 10, 2024
As Trump's personal lawyer, Giuliani was a key figure in the former president's attempts to overturn the 2020 election results and remain in office.
Giuliani disputed that he had been informed ahead of time of the ban.
"John is now telling reporters that I was informed ahead of time of these restrictions, which is demonstrably untrue," Giuliani said in a statement.
"How can you possibly believe that when I've been regularly commenting on the 2020 election for three and a half years. Obviously I was never informed on such a policy, and even if there was one, it was violated so often that it couldn't be taken seriously."
A letter obtained by the AP from Catsimatidis to Giuliani and dated Thursday said Giuliani was prohibited from engaging in discussions relating to the 2020 elections.
"These specific topics include, but are not limited to, the legitimacy of the election results, allegations of fraud effectuated by election workers, and your personal lawsuits relating to these allegations," the letter said.
Ted Goodman, Giuliani's spokesman and adviser, said Giuliani had not known of the directive before Thursday.
"WABC's decision comes at a very suspicious time, just months before the 2024 election, and just as John and WABC continue to be pressured by Dominion Voting Systems and the Biden regime's lawyers," Giuliani said in his statement.
Late last month, Giuliani was one of 18 people indicted by an Arizona grand jury for their roles in an attempt over overturn Trump's loss in 2020. At the time, his spokesman lambasted what he called "the continued weaponisation of our justice system".
Giuliani filed for bankruptcy in December, shortly following a jury's verdict requiring him to pay $US148 million ($A223 million) to two former Georgia election workers for spreading lies about their role in the 2020 election. Despite the verdict, Giuliani continued to repeat his stolen election claims, insisting he did nothing wrong and suggesting he'd keep pressing his claims even if it meant losing all his money or being jailed.
In early April, a New York bankruptcy judge allowed Giuliani to remain in his Florida condo, declining to rule on a motion from creditors that would have forced him to sell the Palm Beach estate. But the judge hinted at more "draconian" measures if the former mayor did not comply with information requests about his spending habits. The next hearing in the case was scheduled for Tuesday.
