Date | Country | Change |
| 1958.01.14 |  Brazil | Territorial Prelature of Carolina was established (from Territorial Prelature of São José do Grajaú and became suffragan of São Luís do Maranhão) |
| 1958.01.14 | Brazil | Diocese of Chapecó was established (from Diocese of Lages and Territorial Prelature of Palmas and became suffragan of Florianópolis) |
| 1958.01.14 | Brazil | Territorial Prelature of Palmas was promoted as Diocese of Palmas (lost territory to establish Diocese of Chapecó) |
| 1958.01.23 |  Dominican Republic | Military Vicariate of Dominican Republic was established |
| 1958.02.02 | Brazil | Diocese of Corumbá lost territory to Diocese of Marília |
| 1958.02.04 | Brazil | Metropolitan Archdiocese of São Luís do Maranhão lost territory to Territorial Prelature of Pinheiro |
| 1958.02.16 | Brazil | Diocese of Cachoeiro de Itapemirim was established (from Diocese of Espírito Santo and became suffragan of Vitória) |
| 1958.02.16 | Brazil | Diocese of São Mateus was established (from Diocese of Espírito Santo and became suffragan of Vitória) |
| 1958.02.16 | Brazil | Diocese of Espírito Santo was promoted as Metropolitan Archdiocese of Vitória (with suffragan sees Cachoeiro de Itapemirim and São Mateus and lost territory to establish Diocese of Cachoeiro de Itapemirim and Diocese of São Mateus) |
| 1958.02.16 |  Mexico | Diocese of Matamoros was established (from Diocese of Ciudad Victoria–Tamaulipas and became suffragan of Monterrey) |
| 1958.02.22 |  Canada | Diocese of Harbour Grace was renamed as Diocese of Harbour Grace–Grand Falls |
| 1958.02.24 |  Congo-Kinshasa | Apostolic Prefecture of Doruma was established (from Apostolic Vicariate of Niangara) |
| 1958.02.24 |  Laos | Apostolic Prefecture of Thakhek was promoted as Apostolic Vicariate of Thakhek |
| 1958.02.24 |  Tanzania | Apostolic Prefecture of Tanga was promoted as Diocese of Tanga (became suffragan of Dar-es-Salaam) |
| 1958.02.25 | Mexico | Diocese of Ciudad Victoria–Tamaulipas was renamed as Diocese of Tampico |
| 1958.03.18 | Mexico | Diocese of Acapulco was established (from Diocese of Chilapa and became suffragan of México) |
| 1958.04.19 | Brazil | Metropolitan Archdiocese of Aparecida was established (from Metropolitan Archdiocese of São Paulo and Diocese of Taubaté and with suffragan sees Lorena and Taubaté) |
| 1958.04.19 | Brazil | Diocese of Botucatu was promoted as Metropolitan Archdiocese of Botucatu (with suffragan sees Assis, Lins and Marília) |
| 1958.04.19 | Brazil | Diocese of Campinas was promoted as Metropolitan Archdiocese of Campinas (with suffragan sees Bragança Paulista, Piracicaba and São Carlos) |
| 1958.04.19 | Brazil | Diocese of Ribeirão Preto was promoted as Metropolitan Archdiocese of Ribeirão Preto (with suffragan sees Jaboticabal and Rio Preto) |
| 1958.04.19 |  Ireland | Diocese of Cork was renamed as Diocese of Cork and Ross (gained territory from the suppressed Diocese of Ross) |
| 1958.04.19 | Ireland | Diocese of Ross was suppressed (to Diocese of Cork and Ross) |
| 1958.04.26 | Brazil | Territorial Prelature of São Peregrino Laziosi no Alto Acre e Alto Purus was renamed as Territorial Prelature of Acre e Purus |
| 1958.04.28 |  Curaçao,  Aruba,  Bonaire, Sint Eustatius and Saba,  Sint Maarten | Apostolic Vicariate of Curaçao was promoted as Diocese of Willemstad (without ecclesiastical province) |
| 1958.04.28 |  Nigeria | Apostolic Prefecture of Ibadan was promoted as Diocese of Ibadan |
| 1958.04.28 |  Pakistan | Diocese of Hyderabad was established (from Metropolitan Archdiocese of Karachi and became suffragan of Karachi) |
| 1958.04.28 |  Peru | Diocese of Abancay was established (from Metropolitan Archdiocese of Cusco and Diocese of Ayacucho and became suffragan of Cusco) |
| 1958.04.30 |  Spain | Diocese of Badajoz exchanged territory with Diocese of Coria–Cáceres |
| 1958.04.30 | Spain | Diocese of Coria–Cáceres exchanged territory with Diocese of Badajoz |
| 1958.05.07 |  Suriname | Apostolic Vicariate of Dutch Guyana–Suriname was promoted as Diocese of Paramaribo (without ecclesiastical province) |
| 1958.05.10 |  Australia,  New Zealand | Apostolic Vicariate of Australia (Ukrainian Rite) was established |
| 1958.05.15 | Peru | Diocese of Huacho was established (from Metropolitan Archdiocese of Lima and became suffragan of Lima) |
| 1958.05.15 | Peru | Territorial Prelature of Huarí was established (from Diocese of Huánuco and Diocese of Huaraz and became suffragan of Lima) |
| 1958.05.15 | Peru | Territorial Prelature of Tarma was established (from Diocese of Huancayo and Diocese of Huánuco and became suffragan of Lima) |
| 1958.05.19 |  Philippines | Diocese of Zamboanga was promoted as Metropolitan Archdiocese of Zamboanga |
| 1958.05.24 |  Venezuela | Diocese of Maturín was established (from Diocese of Ciudad Bolívar and became suffragan of Caracas) |
| 1958.05.25 |  USA | Diocese of Miami was established (from Diocese of Saint Augustine and became suffragan of Baltimore) |
| 1958.06.20 |  Malawi | Apostolic Vicariate of Likuni was renamed as Apostolic Vicariate of Lilongwe |
| 1958.06.21 | Venezuela | Diocese of Ciudad Bolívar was promoted as Metropolitan Archdiocese of Ciudad Bolívar (with suffragan sees Barcelona, Cumaná and Maturín) |
| 1958.06.21 | Venezuela | Diocese of Maracay was established (from Metropolitan Archdiocese of Caracas and Diocese of Calabozo and became suffragan of Caracas) |
| 1958.06.23 |  Burkina Faso | Diocese of Ouahigouya was restored (from Diocese of Koudougou and became suffragan of Ouagadougou) |
| 1958.06.23 | Mexico | Mission sui juris of Tarahumara was promoted as Apostolic Vicariate of Tarahumara |
| 1958.06.23 | Nigeria | Diocese of Umuahia was established (from Diocese of Owerri and became suffragan of Onitsha) |
| 1958.06.23 |  South Africa | Apostolic Prefecture of Volksrust was established (from Metropolitan Archdiocese of Durban, Diocese of Bremersdorp and Diocese of Lydenburg) |
| 1958.06.23 |  South Korea | Apostolic Vicariate of Cheongju 청주 was established (from Apostolic Vicariate of Seul 서울) |
| 1958.06.23 | South Korea | Apostolic Vicariate of Daijeon was established (from Apostolic Vicariate of Seul 서울) |
| 1958.06.23 |  Uganda | Diocese of Arua was established (from Diocese of Gulu and became suffragan of Rubaga) |
| 1958.07.10 | USA | Apostolic Exarchate of United States of America (Ukrainian Rite) was promoted as Metropolitan Archdiocese of Philadelphia (with suffragan see Stamford) |
| 1958.07.10 | USA | Apostolic Exarchate of Stamford (Ukrainian Rite) was promoted as Diocese of Stamford (became suffragan of Philadelphia) |
| 1958.07.11 | Brazil | Diocese of Divinópolis was established (from Metropolitan Archdiocese of Belo Horizonte and Diocese of Aterrado and became suffragan of Belo Horizonte) |
| 1958.07.12 | Philippines | Apostolic Prefecture of Sulu was promoted as Apostolic Vicariate of Jolo |
| 1958.07.20 | Spain | Diocese of Ciudad Rodrigo lost territory to Diocese of Coria–Cáceres |
| 1958.07.20 | Spain | Diocese of Coria–Cáceres lost territory to Diocese of Salamanca |
| 1958.07.20 | Spain | Diocese of Córdoba lost territory to Diocese of Badajoz and Diocese of Málaga |
| 1958.07.20 | Spain | Diocese of Plasencia lost territory to Diocese of Ávila and Diocese of Coria–Cáceres |
| 1958.07.20 | Spain | Diocese of Salamanca lost territory to Diocese of Ciudad Rodrigo and Diocese of Plasencia |
| 1958.07.20 | Spain | Metropolitan Archdiocese of Sevilla lost territory to Diocese of Córdoba |
| 1958.07.30 | Peru | Territorial Prelature of Ayaviri was established (from Diocese of Puno and became suffragan of Arequipa) |
| 1958.09.17 |  India | Apostolic Prefecture of Gorakhpur was renamed as Apostolic Prefecture of Benares-Gorakhpur |
| 1958.11.07 |  Bolivia | Territorial Prelature of Coroico was established (from Metropolitan Archdiocese of La Paz and became suffragan of La Paz) |
| 1958.11.13 |  Papua New Guinea | Apostolic Prefecture of Mendi was established (from Apostolic Vicariate of Port Moresby) |
| 1958.11.22 | Canada | Diocese of Saint Catharines was established (from Metropolitan Archdiocese of Toronto and Diocese of Hamilton and became suffragan of Toronto) |
| 1958.11.22 | Mexico | Diocese of Chihuahua was promoted as Metropolitan Archdiocese of Chihuahua (with suffragan sees Ciudad Juárez and Tarahumara) |
| 1958.11.22 | Mexico | Diocese of Mazatlán was established (from Metropolitan Archdiocese of Durango and Diocese of Sinaloa and became suffragan of Durango) |
| 1958.12.11 |  Gabon | Diocese of Libreville was promoted as Metropolitan Archdiocese of Libreville (with suffragan see Mouila and lost territory to establish Diocese of Mouila) |
| 1958.12.11 | Gabon | Diocese of Mouila was established (from Diocese of Libreville and became suffragan of Libreville) |
| 1958.12.11 |  Madagascar | Diocese of Diégo-Suarez was promoted as Metropolitan Archdiocese of Diégo-Suarez (with suffragan sees Ambanja and Majunga) |
| 1958.12.11 | Madagascar | Diocese of Fianarantsoa was promoted as Metropolitan Archdiocese of Fianarantsoa (with suffragan sees Farafangana, Fort-Dauphin, Morondava and Tuléar) |
| 1958.12.11 | Madagascar | Apostolic Prefecture of Tsiroanomandidy was promoted as Diocese of Tsiroanomandidy (became suffragan of Tananarive) |
