Bishop Liam MacDaid has resigned as Bishop of Clogher due to ill health.
Pope Francis accepted his resignation on Saturday.
Bishop MacDaid was ordained as Bishop of Clogher in July 2010, a cross-border diocese which includes the counties of Monaghan, Fermanagh and portions of Tyrone, Donegal, Louth and Cavan.
He had written to the Pope some months ago on medical advice seeking early retirement.
An administrator will be elected to run the diocese until a new bishop is appointed by the Pope.
Archbishop Eamon Martin praised Bishop MacDaid's gentle pastoral wisdom and his warm concern for others.
"I salute Bishop Liam's generous contribution to Accord Catholic marriage care, his work with the Council for Marriage and the Family of the Episcopal Conference, and his commitment to the religious publisher Veritas, " he said.