| ID | Title  | Author | Language | Number of records | Number of melodies |
|---|---|---|---|---|---|
| 909 | O salutaris hostia | Anonymous | Latin | 1 | 0 |
| 797 | O salutaris hostia alleluia | Anonymous | Latin | 0 | 2 |
| 518 | O salutartis hostia | Anonymous | Latin | 0 | 0 |
| 98 | O sancta propago | Latin | 0 | 0 | |
| 747 | O Sara rara | Anonymous | Latin | 0 | 0 |
| 851 | O svolánie Konstanské | Anonymous | Czech | 0 | 1 |
| 157 | O verbi ales O verbialis | Anonymous | Latin | 1 | 0 |
| 412 | O veri luciferi | Jan Jenštejn | Latin | 0 | 0 |
| 340 | O virgo spes humilium | Anonymous | Latin | 0 | 0 |
| 927 | Octaviano imperatore - Clamet cantet | Anonymous | Latin | 0 | 1 |
| 397 | Od ciesaře nebeského | Anonymous | Czech | 0 | 1 |
| 588 | Od smrti otec nebeský | Anonymous | Czech | 1 | 1 |
| 519 | Odas demus Christo regi Odas demus Cristo regi | Anonymous | Latin | 1 | 0 |
| 299 | Olim te virentibus | Anonymous | Latin | 2 | 1 |
| 38 | Omnes attendite | Anonymous | Latin | 2 | 1 |
| 895 | Omnes christicolae mentes advertite Omnes christicole mentes advertite | Jakub Trch | Latin-Czech | 1 | 1 |
| 520 | Omnis mundus iucundetur Omnis mundus iocundetur | Anonymous | Latin | 2 | 1 |
| 856 | Omnis nunc microcosmus - Omnis mundus | Anonymous | Latin | 1 | 2 |
| 302 | Optimus rerum conditor | Anonymous | Latin | 0 | 0 |
| 759 | Ora virgo spes salutis | Anonymous | Latin | 0 | 0 |
