| Institute | Post-nominal |
|---|
| Canons Regular | C.R. + Initials of specific Congregation e.g. C.R.I.C |
| Canons Regular of Premontré ("Praemonstratensians" or "Norbertines") | O.Praem. |
| Order of St Benedict ("Benedictines") | OSB |
| Order of Cistercians ("Cistercians") | OC |
| Order of Cistercians of Strict Observance ("Trappists") | OCSO |
| Order of Preachers ("Dominicans" or "Blackfriars") Ordinis Praedicatorum | OP |
| Conventual Franciscans ("Franciscans" or "Greyfriars") | OFM Conv. |
| Capuchins Franciscans ("Capuchins") | OFM Cap. |
| Order of Friars Minor ("Franciscans") | OFM |
| Order of St Clare ("Poor Clares") | OSC |
| Order of St Augustine ("Augustinians") | OSA |
| Carmelites of the Ancient Observance ("Carmelites" or "Whitefriars") | O Carm. |
| Discalced Carmelites ("Discalced Carmelites") | O.C.D. |
| Order of Servants of Mary ("Servites") | OSM |
| Brothers Hospitallers of St John of God ("St John of God Brothers") | OH |
| Society of Jesus ("Jesuits") | SJ or SI |
| Institute of the Blessed Virgin Mary ("Loreto Sisters") | IBVM |
| Vincentians | CM |
| Daughters of Charity | DC |
| Congregation of the Most Holy Redeemer ("Redemptorists") | C.Ss.R. |
| Congregation of the Passion ("Passionists") | C.P. |
| Congregatio Sancti Spiritus Holy Ghost Fathers | C.S.Sp. |
| Salesians | SDB |
| Society of the Divine Savior Salvatorians | SDS |
| Society of Mary ("Marists") | SM |
| Marist Brothers | FMS |
| Fratres Scholarum Christianorum ("De La Salle Brothers") | FSC |
| Religious Sisters of Mercy ("Mercy Sisters") | RSM |
| Religious Sisters of Charity ("Irish Sisters of Charity") | RSC |
| Presentation Sisters | IPBVM |
| Congregatio Fratrum Christianorum ("Congregation of Christian Brothers") | C.F.C. |
| Society of St Columban ("Columban Fathers") | SSC |
| Missionary Society of St Patrick ("Kiltegan Fathers") | SPS |
