B
| Babies | The Holy Innocents, Maximus, Nicholas of Tolentino, Philip of Zell |
| Bachelors | Benedict, Benezet, Boniface of Tarsus, Caesarius of Nanzianzen, Casimir of Poland, Christopher, Cuthman, Epipodius, Gerald of Aurillac, Guy of Anderlecht |
| Backward children | Hilary of Poitiers |
| Bacterial disease and infection | Agrippina |
| Bailiffs | Ivo of Kermartin |
| Bakers | Elizabeth of Hungary, Nicholas of Myra, Honoratus |
| Bakers of holy wafers | Honorius of Amiens |
| Bankers | Matthew, Bernardino of Feltre |
| Banking | Michael the Archangel |
| Baptism | John the Baptist |
| Barbers | Cosmas and Damian, Louis, Martin de Porres |
| Barcelona, Spain | Our Lady of Mercy |
| Bari, Italy | Nicholas, Sabinus |
| Barra, Scotland | Finbar |
| Barrel makers | Abdon and Sennen |
| Barren women | Anthony of Padua, Felicity |
| Bartenders, bar keepers, bar staff | Amand |
| Basket makers | Antony the Abbot |
| Battle | Michael the Archangel |
| Baume-les-Messieurs | Drogo |
| Bavaria | Hedwig, Killian |
| Bee Keepers | Ambrose |
| Bees | Ambrose of Milan, Bernard of Clairvaux, Modomnoc |
| Begerin, Ireland | Ibar |
| Beggars | Alexius, Martin of Tours,Giles |
| Belgium | Joseph |
| Bell-founders | Agatha, Fortchern of Trim |
| Bellmakers | Agatha |
| Belt makers | Alexius |
| Benedictine oblates | Henry the Emperor |
| Benevento, Italy | Arthelais, Barbatus of Benevento |
| Bergamo, Italy | Alexander of Bergamo |
| Bergen, Norway | Sunniva |
| Betrayal victims | Epipodius, Flora of Cordoba, Oswin, Philip Howard, Pulcheria |
| Bible scholars | Jerome |
| Bicyclists, cyclists, Bicycle riders | La Madonna di Ghisalo |
| Bird dealers | John the Baptist |
| Birds | Gall |
| Birth pains | Erasmus (Elmo) |
| Bishops | Charles Borromeo |
| Bishops of Latin America | Turibius |
| Black missions, African missions | Benedict the Black, Francis Xavier, Peter Claver, Therese of Lisieux |
| Black people, Negroes, African-Americans | Benedict the Black, Martin de Porres, Peter Claver |
| Blackbirds | Kevin |
| Blacksmiths | Bridgid of Ireland, Dunstan, Eligius (Eloi), Giles, James the Greater, Leonard of Noblac |
| Blind people | Raphael the Archangel, Thomas, Apostle, Cosmas and Damian,Lucy |
| Blood banks | Januarius |
| Blood donors | Our Lady of the Thorns |
| Bodily ills | Our Lady of Lourdes |
| Bodily purity | Agnes of Rome |
| Bohemia | Joseph, Adalbert, John Nepomucene, Cyril and Methodius, Wenceslaus |
| Boilermakers | Eligius (Eloi) |
| Bolivia | Francis Solano, Our Lady of Capucdana (Virgin de la Candelaria), Our Lady of Mt. Carmel, Virgin de la Candelaria, Virgin of Copacabana, La Virgen de Copacabana (Virgin of Copacabana) |
| Bolivian navy | Our Lady of Charity |
| Bologna, Italy | Petronius |
| Bomb technicians | Barbara |
| Bombay, India | Gundisalvus Garcia |
| Book trade | John of God |
| Bookbinders | Celestine V (pope), John of God |
| Bookkeepers | Matthew |
| Booksellers | John of God, Thomas Aquinas |
| Boot blacks, shoe shiners | Nicholas of Myra |
| Bordeaux, France | Simon Stock |
| Borneo | Francis Xavier |
| Boston, Massachusetts, USA | Botulph |
| Bowel disorders | Bonaventure |
| Box makers | Fiacre |
| Boy Scouts | George |
| Boys, young | Dominic Savio |
| Brass workers | Barbara |
| Brazil | Nossa senhora de Aparecida, Peter of Alcantara |
| Breast cancer | Agatha, Aldegundis, Giles, Peregrine Laziosi |
| Breast disease, invoked against | Agatha |
| Breast-feeding | Basilissa, Giles |
| Brescia, Italy | Faustinus |
| Brewers | Augustine of Hippo, Luke, Nicholas of Myra, Amand, Wenceslaus |
| Brick makers | Vincent Ferrer |
| Bricklayers | Stephen |
| Brides | Nicholas of Myra |
| Bridge builders | John Nepomucene, Peter the Apostle |
| Bridges | John Nepomucene |
| Brigands (danger from) | Leonard of Noblac |
| Brittany | Ivo of Kermartin |
| Broadcasters | Gabriel the Archangel |
| Broken bones | Drogo, Stanislaus Kostka |
| Broommakers | Anne |
| Brushmakers | Antony the Abbot |
| Brussels | Michael the Archangel |
| Builders | Vincent Ferrer, Barbara, Thomas, Apostle |
| Building trade | Stephen |
| Bulgaria | Cyril and Methodius |
| Burgos, Spain | Adelelmus |
| Burns | John the Apostle |
| Bursars | Joseph |
| Bus drivers | Christopher |
| Business people | Homobonus |
| Businesswomen | Margaret of Clitherow |
| Butchers | Adrian of Nicomedia, Antony the Abbot, Bartholomew the Apostle, George, Lawrence, Luke the Apostle, Peter the Apostle, Thomas Bellacci, Antony the Abbot, Luke |
| Button makers | Louis |
| Byzantine Eparchy of Van Nuys, Arizona, USA | Holy Protection of the Mother of God |