Three new species of free-living nematodes, Nudora ignava sp. n., Desmodora vietnamica sp. n., and Metachromadora (Metachromadoroides) minor sp. n. from the Mekong River Delta (Vietnam) are described and illustrated. Nudora ignava sp. n. is close to N. omercooperi Inglis 1965, but differs from it in the shorter body, relatively longer oesophagus, greater number of longitudinal cuticular ribs, shorter spicules and gubernaculum, and another shape of gubernaculum. Desmodora vietnamica sp. n. differs from D. communis (Butschli 1874) and D. cuddesae Inglis 1963 in the shorter and thicker body, shorter spicules and a greater number of precloacal supplements. M. (Metachromadoroides) minor sp. n. is similar to M. (Metachromadoroides) complexa Timm 1961, but differs from it in the presence of labial and cephalic sensillae, shorter spicules, and smaller number of precloacal supplements.