Until now a pact between the parties has seen the role rotated.
But Fianna Fail will propose Buncrana-based Rena Donaghey as their candidate – with Fine Gael, Sinn Fein and Labour all getting behind Cllr Frank McBrearty.
The final decision will come down to how many councillors show up for the meeting – and how independents decide to vote. They have said they will back Cllr McBrearty.
But just a few absentees and the vote could go either way.
Councillors will meet today for the county council’s AGM at county chambers in Lifford.
It had been widely anticipated that Labour councillor Frank McBrearty would be the next Mayor.
But Cllr McBrearty says he is confident the Labour party will have the Mayor and Deputy Mayor’s seat come tonight.
“I am working off the basis that there is a power-sharing agreement in place and it is one that has worked very well.
“I’m confident Labour will have the Mayor and deputy Mayor’s position today because Fine Gael, Sinn Fein and the Independents will be true to their word,” he said.
He said if elected as Mayor he will work hard for the people of Donegal and whoever does not agree with him then he will respect that.
“Promoting sport and mental health will be my aim if I am elected as Mayor. I do not want to be side-tracked by this Fianna Fail sideshow.
“They have tried to do it beore and it didn’t work and it won’t work now,” he said.