The Pontifical Orders of Knighthood are secular orders of merit whose membership is conferred on a direct decision of the Pontiff as Head of the Catholic Church and Sovereign of the Vatican City State. Awards are gazetted in Acta Apostolica Sedis, the Gazette of the Holy See. Priests and members of religious orders cannot become papal knights. Diplomas of appointment are issued from the Secretariat of State. Perpetual succession no longer occurs arising from the conferral of a knighthood. Membership of the Association of Papal Orders, for those who wish to join, commences when they receive their diploma of appointment and is conditional on persons remaining in communion with the Church. Non-Catholics who were honoured with a Papal Knighthood by His Holiness are also welcome as members.

For knights and dames of the Pontifical Order of Pius IX (Pian Order):

• Knight or Dame Grand Cross - GCPO
• Knight or Dame Commander – KCPO/DCPO (with or without star)
• Knight or Dame – KPO/DPO

For knights and dames of the Pontifical Order of Saint Gregory the Great:

• Knight or Dame Grand Cross – GCSG
• Knight or Dame Commander – KCSG/DCSG (with or without star)
• Knight or Dame – KSG/DSG

For knights and dames of the Pontifical Order of Saint Sylvester:

• Knight or Dame Grand Cross – GCSS
• Knight or Dame Commander – KCSS/DCSS (with or without star)
• Knight or Dame – KSS/DSS

There are 90 current members, which include thirteen  Dames, distributed among the four Ecclestical Provinces and elsewhere. There are 14 members in the Ecclestical Province of Armagh, 15 in the Ecclestical Province of Cashel & Emly, 25 in the Ecclestical Province of Dublin and 13 in Ecclestical Province of Tuam.  The Diplomatic Corps, Politicians, and Civil Servants account for 13 with a further 10 associated with Ireland but appointed elsewhere. A further 64 awards were made to those serving in the Papal Wars of 1860. There are no current members registered in the Diocese of Ardagh, Clogher, Kilmore, Cashel & Emly,  Killaloe,  Waterford & Lismore and Clonfert.

A total of 348 Knights and Dames have been identified thus far.