| Date | Country | Change |
| 1919 | Apostolic Administration of Eupen–Malmedy–Sankt Vith was established (from Metropolitan Archdiocese of Köln) | |
| 1919 | Titular Episcopal See of Giovanni S. d’Acri (Maronite Rite) was restored | |
| 1919 | Diocese of Chioggia lost territory to Patriarchal See of Venezia | |
| 1919 | Titular Episcopal See of Hamatha (Maronite Rite) was established | |
| 1919 | Titular Archiepiscopal See of Laodicea (Maronite Rite) was established | |
| 1919.02.05 | Military Vicariate of Poland was established | |
| 1919.02.13 | Diocese of Bisignano lost territory to Diocese of Lungro | |
| 1919.02.13 | Diocese of Cassano all’Jonio lost territory to Diocese of Lungro | |
| 1919.02.13 | Archdiocese of Cosenza lost territory to Diocese of Lungro | |
| 1919.02.13 | Ordinariate of Italia continentale (Italo-Albanese Rite) was promoted as Diocese of Lungro (gained territory from Archdiocese of Cosenza, Archdiocese of Rossano, Diocese of Bisignano, Diocese of Cassano all’Jonio and Diocese of San Marco and without ecclesiastical province) | |
| 1919.02.13 | Archdiocese of Rossano lost territory to Diocese of Lungro | |
| 1919.02.13 | Diocese of San Marco lost territory to Diocese of Lungro | |
| 1919.04.03 | Apostolic Vicariate of Congo Belge was renamed as Apostolic Vicariate of Léopoldville (lost territory to establish Apostolic Vicariate of Nouvelle-Anvers) | |
| 1919.04.03 | Apostolic Vicariate of Nouvelle-Anvers was established (from Apostolic Vicariate of Congo Belge) | |
| 1919.04.18 | Apostolic Prefecture of Northern Ontario was established (from Diocese of Haileybury and became suffragan of Ottawa) | |
| 1919.05.22 | Apostolic Vicariate of Chaco was established (from Diocese of Santa Cruz de la Sierra) | |
| 1919.06.03 | Metropolitan Archdiocese of Corfù was renamed as Metropolitan Archdiocese of Corfu–Zakynthos–Kefalonia (gained territory from the suppressed Diocese of Kefalonia–Zakynthos and lost suffragan see Kefalonia–Zakynthos) | |
| 1919.06.03 | Diocese of Kefalonia–Zakynthos was suppressed (to Metropolitan Archdiocese of Corfu–Zakynthos–Kefalonia) | |
| 1919.06.03 | Metropolitan Archdiocese of Naxos was renamed as Metropolitan Archdiocese of Naxos–Andros–Tinos–Mykonos (gained territory from the suppressed Diocese of Tinos–Mykonos and gained suffragan see Crete) | |
| 1919.06.03 | Diocese of Tinos–Mykonos was suppressed (to Metropolitan Archdiocese of Naxos–Andros–Tinos–Mykonos) | |
| 1919.09.10 | Apostolic Prefecture of Bettiah was suppressed (to establish Diocese of Patna) | |
| 1919.09.10 | Diocese of Patna was restored (from the suppressed Apostolic Prefecture of Bettiah and became suffragan of Calcutta) | |
| 1919.09.19 | Diocese of Allahabad lost territory to Diocese of Patna | |
| 1919.10.04 | Territorial Prelature of Acre e Purus was established (from Diocese of Amazonas and became suffragan of Belém do Pará) | |
| 1919.11.19 | Apostolic Prefecture of Celebes was established (from Apostolic Vicariate of Batavia) |
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