Ford, who was campaigning for re-election despite his infamous crack video scandal, was hospitalized earlier this month for an abdominal tumor.
The mayor set to be replaced on the ballot by his brother, Doug Ford, a Toronto city councilor, according to CP24.
"The campaign will be making a statement later in the day," Ford's campaign spokesperson reportedly said while submitting the paperwork for the withdrawal.
Polls have showed Doug Ford has a lower approval rating than his brother and would perform worse in the mayoral race. Citing Doug Ford's low numbers, John Corbett, the vice president of Canadian polling firm Forum Research Inc., said the mayor's withdrawal boded well for the other conservative candidate in the race, John Tory.
The election will be held Oct. 27.
Both Rob and Doug Ford did not immediately respond to a request for comment from Business Insider.
Additional reporting by Hunter Walker.