Tucson Mayor Bob Walkup is not running for re-election.

Walkup, first elected in 1999, is making the announcement in his State of the City Address.

“My fellow Tucsonans, this is my 12th State of the City Address. It will also be my last,” he will say, according to his prepared remarks.

Walkup said it has given him “great joy” to be mayor, “but now Beth and I need to take care of our families and each other.”

He is expected to emphasize ongoing challenges for the community, saying the University of Arizona and K12 education must be protected from budget cuts. He also will make a call for comprehensive immigration reform.

Republican Shaun McClusky is running for the GOP nomination. Attorney Jonathan Rothschild is seeking the Democratic nomination.