The ballot has opened in the race to succeed Mark Drakeford as leader of Welsh Labour.
Wales‘s economy minister Vaughan Gething and education minister Jeremy Miles are both in the running.
Mark Drakeford announced in December that he would be standing down after five and a half years in the role.
The winner of the race is expected to be elected first minister, as Labour currently has 30 of the Senedd‘s 60 seats.
The election of either candidate would be a historic milestone for Wales.
Mr Gething would be the country’s first Black first minister and Mr Miles the first to be openly gay.
Read more: Who are the Labour leadership contenders?
As party members in Wales receive their ballot papers over the coming days, both candidates have renewed their appeals for support.
Mr Gething has pledged to have the NHS as his government’s “budget priority”.
He said it had been a “pleasure listening to and speaking with members right across Wales” and that he would be “honoured” to have their support.
“I believe I have the experience, values and vision to lead a united Welsh Labour movement,” he added.
Mr Miles has said he will focus on a “strong, sustainable economy”.
He said he believes Wales can “flourish as a country” and that the leadership he offered was “bold, hopeful, compassionate, and inclusive”.
“[His leadership is] one where we succeed together,” he added.
The ballot closes on 14 March, with the result announced on 16 March.