Body lengths and widths were measured and body volumes were calculated for 1556 Arctic nema-todes sampled from depths of 8003000 m. The samples were filtered through standard sieves with mesh sizesof 500, 250, 125, 63, and 32 µm. Due to the random orientation of the animal bodies with respect to the sieveplane and the presence of detrital and sediment particles, one can only assess the probabilities of the animalretention over the sieves. The distributions of the logarithms of the body volume and length values of nematodeswere close to the normal distribution on the three finer sieves. A simple mathematical filtration model describ-ing size distribution of nematodes on the sieves is proposed. The limitations for the appli-cation of this relation are discussed.