Endoparasitic sedentary nematodes infecting plant roots are an important problem of modern agriculture. In a compatible interaction with their hosts, cyst nematodes use stylet for mechanical root penetration. The specialized nematode oesophageal glands produce and secrete proteins that facilitate the migration within the root and change morphogenetic program of plant cells. The changes in selected initial cell involve cell cycle reactivation, cell wall modification and boosting of plant primary and secondary metabolism. These leads to the multinuclear syncytium formation, which is the nematode feeding site. Cyst nematode infection activate different plant defense responses, but their active suppression was also observed. The deep understanding of cellular mechanisms involved in syncytium development is essential for the development of new strategies for plant protection against these difficult to control pests.