This is the first of two debates on Tuesday.
The debate will be at the Hilton Hotel at 145 Richmond Street.
Prior to the debate, organizers asked the public to submit questions for the candidates. Much of the focus is said to be the Toronto Foundation's Vital Signs report.
Doug Ford, widely accepted as the third front running candidate based on polling, said he has another engagement and will not be joining the mayoral debate.
The one-on-one debate between Chow and Tory has become a regular occurrence in this campaign. Ford has been somewhat of a rare presence at mayoral debates.
"I think it's a missed opportunity to not have everyone there," said Tory about Ford's absence on Tuesday.
Earlier in the day, Ford announced he received an endorsement. It turned out that endorsement was a quote from Tory in 2010, praising Ford for his business-like approach to governance.