The Plaid Cymru leadership contest winner will be declared later, with Adam Price and Rhun ap Iorwerth challenging Leanne Wood for the job.
Adam Price has won the Plaid Cymru leadership contest, with nearly 50 per cent of the vote.
Carmarthen East and Dinefwr AM Mr Price and Mr ap Iorwerth, assembly member for Ynys Môn, put their hats into the ring after Ms Wood said she would welcome a challenge.
The AM for Carmarthen East and Dinefwr defeated Rhun ap Iorwerth and former leader Leanne Wood.
Rhondda AM Ms Wood has led Plaid Cymru since 2012.
In his victory address, Mr Price said Plaid would form the next Welsh Government in 2021.
The announcement will be made at an event with party supporters in Cardiff.
"This election shows we are ready to lead again," he said. "Our time has come." He takes charge of a group of ten AMs in the assembly.
Counting went to a second round after no candidate has reached 50% of the vote. The declaration is expected to be made at lunchtime.
In the first round of voting Mr Price received 2,863 votes, Mr Ap Iorwerth 1,613 and Ms Wood 1,286, who was knocked out.
Around 6,000 people have taken part in the election - a 71% turnout.
On second preferences, Mr Price gained 618 more votes and Mr ap Iorwerth 348.
Launching their campaigns in July, Mr Price said calls for change in the party could not be put off, while Mr ap Iorwerth called for a debate to "energise the party and the country".
In the final totals, Mr Price beat Mr ap Iorwerth by 3,481 votes to 1,961.
Before joining the assembly in a by-election in 2013, Mr ap Iorwerth was a reporter and presenter for BBC Wales and presented Newyddion on S4C.
Mr Price was MP for Carmarthen East and Dinefwr from 2001 to 2010 and elected to the Welsh Assembly in 2016.
Ms Wood has been an AM since 2003 and was previously a probation officer.
Plaid Cymru has 10 of the 60 assembly members, two fewer than the largest opposition group to Labour in Cardiff Bay, the Conservatives.
This is the third of four leadership contests in the main assembly political parties this year.
In August Gareth Bennett became the new leader of the UKIP group and Paul Davies won the race to lead Conservative AMs earlier this month.
A contest to succeed Carwyn Jones as Welsh Labour leader and first minister is also underway, and will conclude in early December.
Analysis
By Felicity Evans, BBC Wales political editor
So who's going to win?
Well, there's a widespread feeling that Adam Price has the momentum.
That comes with caveats. We don't have a lot of information about what grassroots members think and journalists weren't allowed into hustings.
The other big uncertainty is the voting system - candidates are ranked by preference. Second preference votes could be decisive if no one reaches 50% in the first round.
If Rhun ap Iorwerth were to come third, would his second preferences go to Adam Price because his supporters want a change of leadership?
Would Leanne Wood's supporters make Mr Price their second preference or is there some bad feeling about his criticisms of her at the beginning of the contest? Or could there be a big surprise on the way?
