In his address at the party's annual conference on Saturday, Adams said this will be his past year as its leader and that he will not be a candidate in the next elections, Efe news reported.
Last night, the party voted in favour of a motion to hold a special conference on any decision to enter coalition government, with Mary Lou McDonald telling delegates that those who said Sinn Fein were not interested in government were very wrong. "I have been privileged to be part of an awesome leadership", Adams said.
"Under a new Sinn Fein leader I think anything is possible", said David Farrell, a professor of politics at University College Dublin. "That time is now", Adams said in an emotional speech to a packed party conference.
He is one of the world's longest-serving political leaders, having led the party for 34 years.
The timetable for the 69-year-old's departure from leadership is expected in the next few hours..
The Good Friday agreement gave the province's Catholics a share of power and largely ended a conflict in which some 3,600 people had been killed, many at the hands of Irish republican groups such as the IRA, and others by pro-British unionist paramilitaries and British security forces.
Nitish beats Sharad in battle for arrow
Unhappy with the decision of Nitish Kumar, senior party leader Sharad Yadav chose to part his ways along with some other senior leader.
Adams will nearly certainly hand over to a successor with no direct involvement in the decades of conflict in Northern Ireland, a prospect that would make Sinn Fein a more palatable coalition partner in the Irish Republic where it has never been in power.
A new Sinn Fein leader will also take over responsibility for rescuing power-sharing devolved government in Northern Ireland and avoid a return to full direct rule from London for the first time in decade.
Even so, suspicion of Sinn Fein's role in the Troubles in Northern Ireland still runs deep.
Party delegates elected Adams to carry on as president until 2018 and agreed to hold a special conference to discuss the new leadership.
Adams also announced on Saturday that he would not stand for re-election to the Dublin parliament, where he has sat since 2011, moving Sinn Fein from the fringes to become the Irish Republic's third party and its main left-wing force.