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