Abstract. Silicon carbide (SiC) nanoparticles are widely used in industrial applications; however, some reports indicate they are safe while others claim the opposite. We aimed to characterize the physicochemical properties of SiC nanoparticles and investigate their impact on the multicellular animal model, Caenorhabditis elegans and the plant parasitic nematode Meloidogyne incognita. The X-ray diffractogram patterns and chemical analyses confirmed that the content is SiC. Furthermore, N 2 sorption isotherm analyses revealed that Brunauer-Emmett-Teller (BET) surface area was 37.6 m²/g and single point adsorption total pores volume of pores less than 126.1853 nm in diameter at p/p° = 0.984417366 was 0.124975 cm³/g. Furthermore, adsorption average pore width was 13.26382 nm. Scanning electron microscopy showed that the SiC nanoparticles have a semi-crystalline shape with uncompleted faces. Some edges are angular whereas others are curved and smooth with an average particle size of 50 nm ± 21.5. The bioassays indicated that SiC nanoparticles did not affect hatching of larvae of both nematodes, whereas they affected dramatically the survival of the first stage larvae (L1) of C. elegans, but not the second stage juveniles J 2 s of M. incognita. There was no effect of SiC on length and width of the dead L1; however, internal organs, particularly the intestine, exhibited black color indicating uptake of the SiC nanoparticles.