Gerry Adams has announced his intention to step down as Sinn Fein president in 2018.
The 69-year-old republican veteran told the annual Sinn Fein Ard Fheis in Dublin it would be his last as leader, and a special meeting of the party would be called next year to elect a successor.
The TD for Co Louth, who has been party president since 1983, also told delegates he would not run in the next election in the Irish Republic.
"Leadership means knowing when it is time for change and that time is now," he told the annual conference in the RDS arena in Dublin.
Mr Adams said the move was part of the ongoing process of leadership transition within the party.
The plan, formulated along with Martin McGuinness before his death earlier this year, has already seen Michelle O'Neill, 40, take the role of Sinn Fein's leader at Stormont.
Mr Adams has gone before the Ard Fheis to seek re-election every year since 1983 and that formality was repeated on Saturday night.
But in his leader's speech, he told republican faithful it would be the last time he would put himself forward for the role.
"I want to thank everyone who has welcomed me into their homes and communities and have made me part of countless campaigns, countless elections and countless negotiations," he said.
Amid rapturous applause and a standing ovation, Mr Adams told delegates: "We are going to continue to go forward."
He paid special tribute to his wife Collette and son Gearoid.
The long-standing MP for west Belfast switched his focus to the Dublin parliament in 2011, becoming a TD for Co Louth.
Sinn Fein has made steady gains in the Irish Republic in recent polls but many believe the prospects of further growth is limited due to the presence of Troubles era figures.
Current deputy leader Mary Lou McDonald, 48, will be a clear favourite to succeed Mr Adams.
The Ard Fheis also saw the party faithful debate its position on abortion.
Delegates voted to partially liberalise the party's stance, setting its position ahead of next year's referendum in the Irish Republic on the clause of the state's constitution that frames its strict laws on terminations.
The conference was also the first since Mr McGuinness died in March. His widow Bernie attended as tributes were paid to the former IRA commander turned Stormont deputy first minister.