Three mononchid nematode species new for the Slovak Republic were recorded in forest ecosystems. In regularly-flooded forests with Fraxineto-Salicetum vegetation, the species Mylonchulus andrassyi and Tigronchoides ginglymodontus were recorded; in soil with the Querceto-Carpinetum forest type, the species Miconchus hopperi was observed. Comments on the morphometrical characteristics and ecology of the recorded species are presented here.