A species list and the quantitative distribution of free-living nematodes in six water bodies of Taimyr Peninsula are given. Four new species are described and figured. Tobrilus affinis sp. nov. differs from the similar T. undophylus by lesser body size (L = 1911-2460 µm), longer head setae (13-15 µm), shorter (46-54 µm) spicules in males and the presence of biocrystals. T. modestus sp. nov. is closely related to T. trypilus, but differs from it by shorter body (L = 1188-1135 µm), head setae (4 µm), tail (6.5-7.2 times anal diameter), spear (13-17 µm) and shorter prerectum (60-75 µm) of female. Eumonhystera maxima sp. nov. is closely related to E. filiformis, but differs from it by longer body (0.6-0.8 µm), shorter tail (9-12 times anal diameter) and more anterior position of amphid. The descriptions and figures of Eumonhystera papuana found for the first time in European water bodies and the male of Tobrilus helveticus which is recorded from Russia for the first time, are given.