"We have robocalled before and we'll robocall next year. That’s how you invite people," Ford said Wednesday.
"It's virtually impossible to get to everyone's door with an invitation. The most efficient way, cost-effective way is robocalling people and inviting them to the event."
He said that Ford Fest has grown well beyond its original size, when his father first organized it almost two decades ago.
"My dad started it in 1995 to give back to the community. It was a little smaller back then, now it's very large," he said.
It was initially held in his parents' backyard. Since then, it has been held in other places and on multiple occasions in some years.
This year's first Ford Fest is scheduled to take place at Thomson Park on Friday. The mayor has faced criticism that it is functioning as a campaign event, though Ford denies this is the case.
There won't be any alcohol at this Ford Fest, as the province has turned down the organizers' application for a liquor licence for the event.
Ford said there is no plan to end the party any time soon.
"I'll assure you, we've been doing this for 19 years and we're going to continue to do it for the next 19 years," he said.
"We like giving back to the community. We want people to come. Everybody's invited."
Ford, a 45-year-old father of two, is seeking re-election this fall. He is up against dozens of candidates, including a handful of high-profile contenders that include Olivia Chow and John Tory.
The mayor said that "the other councillors, the other candidates" are welcome to attend Ford Fest, along with anyone else in the city.
Ford also said he was "confident" he would be re-elected on Oct 27.