| Nominativ | fideicommissarium, fideicommissarius, fideicommissaria | fideicommissaria, fideicommissarii, fideicommissariae |
| Genitiv | fideicommissarii, fideicommissarii, fideicommissariae | fideicommissariorum, fideicommissariorum, fideicommissariarum |
| Dativ | fideicommissariae, fideicommissario, fideicommissario | fideicommissariis |
| Akkusativ | fideicommissariam, fideicommissarium, fideicommissarium | fideicommissaria, fideicommissarios, fideicommissarias |
| Ablativ | fideicommissario, fideicommissario, fideicommissaria | fideicommissariis |
| Vokativ | fideicommissarium, fideicommissarie, fideicommissaria | fideicommissaria, fideicommissarii, fideicommissariae |
