The public was invited to tell a special town hall meeting of Toronto and East York community council how it feels about the issue.
About 40 speakers registered to give their opinion and another 300 showed up to fill the gallery.
NDP MPP Peter Tabuns kicked off the meeting calling casinos "a shell game" where "the house always wins."
Others predicted an increase in crime and other problems associated with gambling.
Jason Applebaum, a recovering gambler, said he hates the idea of a casino in Toronto.
"In my experiences the proximity to a casino just increases addiction," he said.
But supporters said it would bring jobs to the city and is too good an idea to turn down.
The Canadian Autoworkers Union, says it isn't against the idea of a casino as long as the jobs are unionized.
"There has to be some balance to the debate. There are jobs here — some good paying jobs — jobs that support families. Casino workers certainly pay taxes," said CAW spokesman Bob Orr. The Canadian Gaming Association held a pre-meeting news conference where it outlined the advantages to a casino.
Bill Rutsey, CEO of the association, called it a "once in a lifetime opportunity."
City staff members presented a report on where in the city zoning would allow for a casino.
Councillors were also scheduled to get reports from Toronto Police, Toronto Public Health and parking officials.
The Ontario Lottery and Gaming Corporation says a casino in downtown Toronto could create 12,000 jobs .
But Theo Lagakos who works at Woodbine says those figure might be misleading.
"The OLG has already closed three facilities and where I work it has already laid off 30 full-time employees just last week. So I really don't trust the provincial government and the numbers they are giving," he said.
The town hall meeting will not end with a resolution — but the meeting was a chance for councillors to gauge public opinion.
The full city council will receive a report from city staff in early November outlining the pros and cons of the idea.
Provincial officials have said they won't build a casino where it isn't wanted.Suggest a correction