Some 3,000 party members are attending the party's conference, which began yesterday in Dublin.
Motions on the party's position on abortion will be debated this evening.
Having led Sinn Fein for 34 years, Gerry Adams is expected to run unopposed for the presidency of the party today, but will set the scene for who will replace him as leader at 8:30pm.
Mr Adams has said he wants party members to hear of his plans first, so no advance notice has been given of his speech, but deputy leader Mary Lou McDonald has long been tipped as the natural successor.
This evening the party will hear debate on repealing the 8th amendment of the Constitution, but is expected to maintain its position that members cannot vote according to their conscience, but rather must follow the party line.