President Mary McAleese leads a ceremony marking the 92nd anniversary of the 1916 Rising today.
A party of 350 members of the Defence Forces will be involved in the commemoration at the GPO on O'Connell Street in Dublin, which is due to begin at 12 noon.
A guard of honour will be inspected by President Mary McAleese who will be joined by the Taoiseach Bertie Ahern, the Minister for Defence Willie O'Dea and the Defence Forces Chief of Staff, Lieutenant General Dermot Earley.
The President will lay a wreath followed by a minutes silence and the National Anthem.
The ceremony will culminate with a fly past by the Air Corps above the GPO.
Meanwhile, republicans are gathering at dozens of locations around the country for the annual Easter commemorations.
Sinn Fein President Gerry Adams is speaking in Dublin and is asking supporters to celebrate the spirit of 1916 and work together for Irish re-unification.
Personally, he said, he would be reflecting on the past as well as the difficulties that lie ahead.