Unlike the digital voting systems widely used by other parties to broaden participation, about 750 voting delegates and more than 200 observers are meeting this weekend at the St. John's Convention Centre.
They will choose from among three former cabinet ministers, Paul Davis, John Ottenheimer and Steve Kent.
Supporters for each camp waved placards, yelled and beat blue thunder sticks for their candidate as they were introduced by three members of the Young Progressive Conservatives.
Under provincial law, whoever wins must call an election within 12 months of being sworn in as premier.
The Tories have held majority power since 2003 and were a steamrolling force under former premier Danny Williams.
But in recent months the party has slid in popularity, well behind the Opposition Liberals. It has also lost four consecutive byelections — three of them in districts that were held by senior cabinet ministers, including former premier Kathy Dunderdale.
Dunderdale stepped down Jan. 24 amid questions about her leadership.
The first attempt to replace her ended when all three candidates withdrew. The process started again in July.
"Friends, we have sailed through some rough waters," Natural Resources Minister Derrick Dalley, a Davis supporter, told the crowd.
"Our decision this weekend is about who can win the election in 2015 and who is best to lead Newfoundland and Labrador for the next decade.
"Something is missing in our party," Dalley said of its recent troubles. "It has to change."
It's widely believed the race is close and it's expected none of the three candidates will get the required 50 per cent plus one on the first ballot when voting takes place Saturday. The third place finisher will drop off before the second ballot.
Earlier Friday, Premier Tom Marshall thanked his colleagues and packed up his office as he prepared to retire from the top job.
Marshall took over as premier on an interim basis after Dunderdale quit and stayed on through the party's first aborted leadership process.
Marshall poked fun Friday at the Tories' leadership struggles during a lighthearted speech at the Confederation Building. The audience of public servants roared and clapped as he joked that he had just heard breaking news that the three latest candidates had also pulled out.
Marshall thanked those in the crowd for their hard work during his time in government.
"One thing I learned when I came here is the good people, the strong professional people that we have here," he said.
(VOCM, The Canadian Press)