The new Scottish Labour leader is set to be announced, seven months after Iain Gray said he was stepping down from the job.
For the first time, whoever is elected to succeed him will head the party across the country rather than just its Holyrood group.
Mr Gray, who has held the top job for three years, declared he was stepping down after the Scottish National Party's landslide victory in May's Scottish election.
Several leading Labour politicians north of the border lost their seats, with Mr Gray conceding at the time that it was a "dreadful night".
Now three candidates are in the running to succeed him: MP Tom Harris, MSP Johann Lamont, the current Scottish Labour deputy leader, and MSP Ken Macintosh, the party's culture spokesman.
The contest has been keenly fought, with Mr Harris regarded by some as more of an outsider.
More than 300,000 ballot papers were sent out last month, with members of the party, affiliated trade unions and other organisations all given a say in who the new leader should be.
Voting in the contest closed on Wednesday and the result will be declared on Saturday in Edinburgh.
Following the party's heavy defeat by the SNP, Mr Gray said Labour needs to learn some "very hard and fundamental lessons".
Since then Labour agreed to establish an overall Scottish leader, a move which distances the party from Westminster control and opens the way for MPs and MEPs to hold senior positions.