Cornett's announcement sets up a potential contest with first-term City Councilman Ed Shadid.
Shadid, who represents Ward 2 in inner northwest Oklahoma City, announced his plans to run earlier this summer and has opened a campaign office downtown.
He plans a rally Aug. 15 at the Farmers Public Market, where a transit forum he sponsored drew about 500 people in February.
Shadid has raised persistent questions about the viability of projects such as the downtown streetcar and the convention center included in MAPS 3.
Shadid said Monday that the election would be a “referendum on how we make decisions.”
He said the next mayor needs to be more fiscally responsible and more inclusive, put neighborhood interests over special interests and “govern with a higher ethical standard.”
“We've come to a fork in the road,” Shadid said.
Shadid, a spinal surgeon, earlier this year circulated a memo to potential campaign advisers in which he said he expected to spend $750,000 to $1.5 million on the race.
Cornett, a former television news reporter and anchor, was in his first term on the city council when he was elected mayor in 2004. He was re-elected in 2006 and in 2010.
Two other potential candidates, Oklahoma County Commissioner Brian Maughan and oil and gas executive Jeff Cloud, previously said they would not run if Cornett sought re-election.
Cornett said he thought the election would center on where the city is headed.
“In other words, do you think the city is headed in the right direction or not? And if you think the city's heading in the right direction, I think we stand a good chance of winning.”
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