Ed Stelmach will step down as premier and leader of the Alberta Progressive Conservative Party on Oct. 1.
The date came in a resignation letter Stelmach sent Friday to party president Bill Smith, four months after he first announced he was stepping down.
"With this letter I hereby inform you of my intention to resign as leader of our party effective October 1, 2011," Stelmach writes. "I ask that pursuant to our constitution, you initiate the process to select my successor."
Nomination of candidates will start June 17 and continue until July 15. The first ballot in the vote for a new leader will take place Sept. 17.
If no one receives more than half the votes that day, a second ballot with the top three candidates will be held Oct. 1.
Only members of the Alberta Progressive Conservative Party can vote for a new leader. People who wish to join can do so online up to 24 hours before polls open for each ballot.
So far, former cabinet ministers Ted Morton, Alison Redford, Doug Horner, Gary Mar, Rick Orman and Battle River-Wainwright MLA Doug Griffiths have announced they are seeking the party leadership.