The Roman Catholic Diocese of Poreč and Pula (Croatian: Porečko-pulska biskupija; Latin: Dioecesis Parentina et Polensis; Italian: Diocesi di Parenzo e Pola) is a suffragan Latin diocese in the ecclesiastical province of the Metropolitan Archdiocese of Rijeka on Istria peninsula, in Croatia.

The cathedral episcopal see is Euphrasian Basilica, a Minor basilica and World Heritage Site in the city of Poreč. The Co-Cathedral is the Cathedral of the Assumption of the Blessed Virgin Mary in Pula. There are two more former cathedrals: Crkva Sv. Pelagije, in Novigrad, and Crkva Navještenja BDM, in Pićan.

• Established circa (200-)300 as Diocese of Parentium; medieval/modern names Poreč (Croat) / Parenzo (Italian) / Parentin(us) (Latin adjective)
• Exchanged territory in 1784 with the Italian Diocese of Trieste
• Formally United aeque principaliter (i.e. in personal union) with the Diocese of Cittanova but only 1442–1448
• Renamed on June 30, 1828 as Diocese of Parenzo/Poreč and Pola/Pula, having gained territory from the suppressed Diocese of Pula
• Gained territory on 1977.10.17 from the Diocese of Trieste, and exchanged territory with Diocese of Koper.

As per 2014, it pastorally served 169,048 Catholics (79.5% of 212,561 total) on 2,839 km in 135 parishes with 108 priests (94 diocesan, 14 religious), 1 deacon, 78 lay religious (48 brothers, 30 sisters) and 6 seminarians.

(all Roman rite; probably many Italians, notably in the early centuries)

Bishops of Poreč

• Andrea (991 – 1010?)
• Sigimbaldo (1015 – 1017?)
• Engelmaro (1028 – 1040)
• Arpo (1045 – 1050)
• Orso (1050 – 1060)
• Adelman (1060 – 1075)
• Cadolo (1075 – 1082)
• Pagano I (1082 – 1104)
• Bertold (1104 – 1120)
• Ferongo (1120 – 1131)
• Rodemondo (1131 – 1146)
• Vincenzo (1146 – 1158)
• Uberto (1158 – 1174)
• Pietro (1174 – 1194)
• Giovanni I (1196 – 1200)
• Pulcherio (1200 – 1216?)
• Adalberto (1219 – 1243)
• Pagano II (1243 – 1246)
• Giovanni II (1249 – 1254)
• Ottone (1256 – 1282)
• Bonifazio (1282 – 1305)
• Giuliano Natale (1306 – 1309)
• Graziadio, Carmelite Order (O. Carm.) (1309 – 1327)
• Giovanni Gottoli de Sordello, Dominican Order (O.P.) (1328.06.20 – death 1367)
• Gilberto Zorzi, O.P. (1367.07.02 – 1388.03.04), next Bishop of Eraclea (1388.03.04 – death 1403)
• Giovanni Lombardo, O. Carm. (1388.06 – death 1415.03.21)
• Fantino Valaresso (1415.04.28 – 1425.12.05), later Metropolitan Archbishop of Crete (insular Greece) (1425.12.05 – death 1443.05.18)
• Daniele Scotto de’ Rampi (1426 – 1433), next Bishop of Concordia (Italy) (1433.01.07 – death 1443.07.11)
• Angelo Cavazza (1433.01.07 – 1440.04.11); previously Bishop of Arba (1433.01.07 – 1440.04.11); later Bishop of Cittanova (1442 – retired 1448); died 1457
• Placido de Pavanello, Vallombrosians (O.S.B. Vall.) (1457.01.24 – 1464.11.05); previously Titular Bishop of Byblus (1454.01.09 – 1457.01.24); later Bishop of Torcello (1464.11.05 – 1471)
• Francesco Morosini, Benedictine Order (O.S.B.) (1464.11.14 – death 1470.10.03), also Apostolic Administrator of Macerata (Italy) (1470.02.02 – 1470.10.03) and Apostolic Administrator of Recanati (Italy) (1470.02.02 – 1470.10.03)
• Bartolomeo Barbarigo (1471.10.11 – died after 1475.06.03)
• Silvestro Quirini (1476.01.31 – died about October 1476)
• Niccolò Franco (1476.10.23 – 1485.02.21 appointed bishop of Treviso)
• Tommaso Catanei (or Colleoni), O.P. (1485.03.04 – 1485.12.12 appointed bishop of Cervia)
• Giovanni Antonio Pavaro (1487.03.14 – 1500.02.20)
• Alvise Tasso (1500.02.24 – 1516.01.16 appointed bishop of Recanati)
• Girolamo Campeggi (1516.03.14 – retired 1533)

Apostolic Administrator Cardinal Lorenzo Campeggio (1533.06.06 – 1537.05.28)

• Giovanni Campeggi (1537.05.28 – 1553.05.06 appointed bishop of Bologna)
• Pietro Gritti (1553.05.17 – 1573.02.09)
• Cesare Nores (1573.02.09 – 1597.12.12)
• Giovanni Lippomano (1598.07.08 – retired after 1608.06.09)
• Leonardo Tritonio (1609.02.09 – 1631.06.15)
• Ruggero Tritonio (1632.02.01 – 1644.07.25)
• Giovan Battista Del Giudice (1644 – 1666.01.24)
• Niccolò Petronio Caldana (1667.03.16 – died October 1670)
• Alessandro Adelasio, C.R.L. (1671.07.01 – died August 1711)
• Antonio Vaira (1712.03.02 – 1717.07.12 appointed bishop of Adria)
• Pietro Grassi (1718.03.14 –1731.03.16)
• Vincenzo Maria Mazzoleni, O.P. (1731.05.21 – 1741.12.16)
• Gaspare Negri (1742.01.22 – died January 1778)
• Francesco Polesini (1778.06.01 – 1819.01.09)

No bishop (1819 – 1827)

Suffragan Bishops of Poreč and Pula

TO BE ELABORATED

• Juraj Dobrila (1857.12.21 – 1875)
• Giovanni Nepomuceno Glavina (1878.09.13 – 1882.07.03)
• Alojzij Zorn (1882.09.25 – 1883.08.09)
• Giovanni Battista Flapp (1884.11.13 – 1912)
• Trifone Pederzolli (1913.06.19 – 1941.04.22)
• Raffaele Mario Radossi, O.F.M. Conv. (1941.11.27 – 1948.07.07)
• Apostolic Administrator Bishop Dragutin Nežić (1950.05.21 – 1960.06.15)
• Bishop Dragutin Nežić (1960.06.15 – 1984.01.27)
• Bishop Antun Bogetić (1984.01.27 – 1997.11.18)
• Bishop Ivan Milovan (1997.11.18 - 2012.06.14)
• Bishop Dražen Kutleša (2012.06.14 – 2020.07.11)
• Apostolic Administrator, Archbishop Dražen Kutleša (2020.07.11 – 2023.03.18)
• Bishop Ivan Štironja (since 2023.01.21)

• Roman Catholicism in Croatia
• Istria County
• History of Istria

• Diocese website (in Croat)

45°13′43″N 13°35′36″E / 45.2286°N 13.5933°E / 45.2286; 13.5933