| Celebration | Name | Saint | Birth | Death |
|---|---|---|---|---|
| 4 of January | Isabel | Saint Isabel Ana Seton | 1821 United States | |
| 15 of January | Ita | Saint Ita | 570 Ireland | |
| 21 of January | Inés | Saint Agnes | Italy | |
| 23 of January | Ildefonso | Saint Ildephonse | 667 Spain | |
| 4 of February | Isidoro | Saint Isidoro of Pelusio | 449 Egypt | |
| 5 of February | Ingenuino | Saint Ingenuino | 605 Italy | |
| 5 of February | Isabel | Blessed Elizabeth Canori Mora | 1825 Italy | |
| 19 of February | Isabel | Blessed Isabel Picenardi | 1468 Italy | |
| 22 of February | Isabel | Blessed Isabelle of France | 1225 France | 1270 France |
| 1 of March | Inés | Saint Inés Cao Kuiying | 1856 China | |
| 2 of March | Inés | Saint Inés of Praga | 1282 Czech republic | |
| 3 of March | Inocencio | Blessed Innocent of Berzo Scalvinoni | 1890 Italy | |
| 12 of March | Inocencio | Saint Innocent I, pope | Italy | 417 Italy |
| 19 of March | Isnardo | Blessed Isnard of Chiampo | 1244 Italy | |
| 2 of April | Isabel | Blessed Elizabeth Vendramini | 1860 Italy | |
| 2 of April | Iván | Blessed Ivan Ziatyk | 1899 Poland | 1952 Russian federation |
| 5 of April | Irene | Saint Irene | 204 Macedonia, the former yugoslav republic of | |
| 6 of April | Ireneo | Saint Ireneo | Hungary | |
| 11 of April | Isaac | Saint Isaac of Spoleto | Syrian arab republic | 550 Italy |
| 13 of April | Ida | Blessed Ida of Boulogne | 1113 France | |
| 13 of April | Ida | Blessed Ida de Val-des-Roses | 1290 France | |
| 14 of April | Isabel | Blessed Isabel Calduch Rovira | Spain | |
| 17 of April | Inocencio | Saint Inocencio of Tortona | Italy | |
| 18 of April | Idesbaldo | Blessed Idesbald of Dune | 1167 Belgium | |
| 20 of April | Inés | Saint Agnes of Montepulciano | 1270 Italy | 1317 Italy |
| 26 of April | Isidro | Saint Isidore of Seville | 556 Spain | 636 Spain |
| 9 of May | Isaías | Saint Isaiah prophet | ||
| 10 of May | Iván | Blessed Ivan Merz | 1896 Bosnia and herzegovina | 1928 Croatia (Hrvatska) |
| 11 of May | Iluminado | Saint Iluminado monje | ||
| 11 of May | Ignacio | Saint Ignacio of Láconi | 1701 France | 1781 France |
| 11 of May | Iluminado | Saint Iluminado of Saint Severino | Italy | Italy |
| 12 of May | Imelda | Blessed Imelda Lambertini | 1322 Italy | 1333 Italy |
| 13 of May | Inés | Saint Inés of Poitiers | France | 588 France |
| 14 of May | Isidoro | Saint Isidoro of Quío | Greece | |
| 15 of May | Isidro | Saint Isidore the Laborer | 1080 Spain | 1130 Spain |
| 19 of May | Ivo | Saint Yves | 1303 France | |
| 1 of June | Iñigo | Saint Íñigo of Oña | Spain | 1057 Spain |
| 1 of June | Isquirión | Saint Isquirión y compañeros | 250 Egypt | |
| 5 of June | Ilidio | Saint Ilidio of Arvernia | 384 France | |
| 7 of June | Isaac | Saint Isaac of Córdoba | Spain | 851 Spain |
| 10 of June | Itamar | Saint Itamar of Rochester | United kingdom | 656 United kingdom |
| 11 of June | Ignacio | Blessed Ignatius Maloyan | 1869 Turkey | 1915 Turkey |
| 12 of June | Inocencio | Blessed Innocent Guz | Poland | 1940 Germany |
| 15 of June | Isfrido | Saint Isfrido of Ratzeburg | 1204 Germany | |
| 17 of June | Isauro | Saint Isauro | ||
| 18 of June | Isabel | Saint Isabel of Schönau | 1126 Germany | 1164 Germany |
| 22 of June | Inocencio | Blessed Innocent V pope | 1245 France | 1276 Italy |
| 28 of June | Ireneo | Saint Irenaeus of Lyon | 130 Turkey | 202 France |
| 1 of July | Ignacio | Blessed Ignatius Falzon | 1865 Malta | |
| 3 of July | Ireneo | Saint Ireneo of Chiusi | 273 Italy | |
| 4 of July | Isabel | Saint Isabel of Portugal | 1271 Spain | 1336 Portugal |
| 7 of July | Ifigenia | Blessed Iphigenia of Saint Matthew | 1794 France | |
| 12 of July | Inés | Saint Inés Lê Thi Thành (Dê) | Viet nam | 1841 Viet nam |
| 15 of July | Ignacio | Blessed Inacio of Azevedo and companions | Spain | 1570 |
| 16 of July | Irmengardis | Blessed Irmengarde of Frauenwörth | 866 Germany | |
| 31 of July | Ignacio | Saint Ignatius of Loyola | 1491 Spain | 1556 Italy |
| 4 of August | Ia | Saint Ia | Iran | 632 Iran |
| 14 of August | Isabel | Blessed Elisabetta Renzi | 1859 Italy | |
| 17 of August | Ierón | Saint Ierón of Frisia | 856 | |
| 2 of September | Ingrid | Blessed Ingrid Elofsdotter | Sweden | 1282 Sweden |
| 4 of September | Ida | Saint Ida of Herzfeld | 825 Germany | |
| 4 of September | Irmgarda | Saint Irmgarda of Süchteln | 1089 Germany | |
| 8 of September | Isaac | Saint Isaac of Armenia | 438 Armenia | |
| 8 of September | Ismael | Blessed Ismael Escorihuela Esteve | 1902 | 1936 Spain |
| 21 of September | Ifigenia | Saint Ifigenia vírgen | ||
| 22 of September | Iraides | Saint Iraides vírgen y mártir | ||
| 22 of September | Ignacio | Blessed Ignacio Casanovas | 1893 Spain | 1936 Spain |
| 22 of September | Ignacio | Saint Ignacio of Saintdone | 1686 Italy | 1770 Italy |
| 24 of September | Isarno | Saint Isarno of Marsella | 1043 Italy | |
| 30 of September | Ismidón | Saint Ismidón of Die | 1115 France | |
| 6 of October | Isidoro | Blessed Isidore of Saint Joseph de Loor | 1881 Belgium | 1916 Belgium |
| 9 of October | Inocencio | Saint Inocencio of la Inmaculada Canoura y compañeros | 1934 Spain | |
| 17 of October | Ignacio | Saint Ignatius of Antioch | 35 Turkey | 107 Italy |
| 17 of October | Isidoro | Saint Isidoro Gagelin | 1833 China | |
| 19 of October | Isaac | Saint Isaac Jogues | 1646 Canada | |
| 19 of October | Inés | Blessed Agnes of Jesus Galand | 1634 France | |
| 20 of October | Irene | Saint Irene of Tancor | Portugal | 653 Portugal |
| 23 of October | Ignacio | Saint Ignacio of Constantinopla | 877 Turkey | |
| 3 of November | Ida | Saint Ida of Fieschingen | 1226 Switzerland | |
| 5 of November | Isabel | Saint Isabel | Israel | Israel |
| 6 of November | Ildefonso | Blessed Ildefonso Luis | Spain | Spain |
| 6 of November | Indalecio María | Blessed Indalecio María | Spain | Spain |
| 6 of November | Inocencio | Blessed Inocencio García Díez | Spain | Spain |
| 6 of November | Isabelino | Blessed Isabelino Carmona Fernández | Spain | Spain |
| 6 of November | Isaías María | Blessed Isaías María | Spain | Spain |
| 6 of November | Isidro | Blessed Isidro Mediavilla Campo | Spain | Spain |
| 6 of November | Isidro | Blessed Isidro Ordoñez Díez | Spain | Spain |
| 6 of November | Ismael | Blessed Ismael | Spain | Spain |
| 6 of November | Iltuto | Saint Iltuto of Gales | 511 United kingdom | |
| 8 of November | Isabel | Blessed Elizabeth of the Trinity | 1880 France | 1906 France |
| 8 of November | Isaías | Blessed Isaiah Boner | Poland | 1471 Poland |
| 9 of November | Isabel | Blessed Elizabeth of the Holy Trinity Catez | 1906 France | |
| 16 of November | Inés | Saint Inés of Asis | 1197 Italy | 1253 Italy |
| 17 of November | Isabel | Saint Isabel of Hungary | 1207 Hungary | 1231 Germany |
| 17 of November | Ilda | Saint Ilda of Inglaterra | United kingdom | United kingdom |
| 24 of November | Inés Tsao Kui | Blessed Agnes Tsao Kui | ||
| 25 of November | Isabel | Blessed Elizabeth Achler | Germany | 1420 Germany |
| 28 of November | Irenarco | Saint Irenarco | Armenia | Armenia |
| 29 of November | Iluminada | Saint Iluminada | Italy | 320 Italy |
| 2 of December | Iván | Blessed Ivan Slezyuk | Ukraine | 1973 Ukraine |