The expression of the genes encoding the inhibitors of serine (ISP) and cysteine proteinases (ICP) was studied in the roots of tomato plants resistant and susceptible to the root-knot nematode Meloidogyne incognita during infection and under the effects of signaling molecules: salicylic (SA) and jasmonic (JA) acids. It was shown that, upon infection, resistant plants are characterized by an increased accumulation of transcripts of the ICP and ISP genes at the stages of penetration and development in the roots, while the level of transcription does not change in susceptible plants. There was a significant decrease in nematode invasion in susceptible plants after treatment with SA or JA compared to untreated plants, which makes it possible to determine the role of the studied proteinase inhibitors in resistance induced by signaling molecules. It was revealed that an increase in expression of the genes of proteinase inhibitors is accompanied by inhibition of the reproductive potential and size of M. incognita females, as well as by a decrease in plant infection.