| Singular | Plural | |
|---|---|---|
| Nominativ | congrus, congrus | congri, congri |
| Genitiv | congri, congri | congrorum, congrorum, congrum, congrum |
| Dativ | congro, congro | congris, congris |
| Akkusativ | congrom, congrom, congrum, congrum | congros, congros |
| Ablativ | congro, congro | congris, congris |
| Vokativ | congre, congre, congregenetur, congresui | congri, congri |