Plant-parasitic nematodes, like root-knot and cyst nematodes, usurp and modulate the plant cell cycle machinery in their favour. Both, the plant mitotic cycle and the endocycle, are essential targets for a successful susceptible interaction between the host plant and these pathogens. Key cell cycle genes, as well as their inhibitor genes, are important components to allow the induction and maintenance of the nematode feeding site (NFS) development. Giant cells undergo acytokinetic mitosis and DNA endoreduplication and are surrounded by rapidly dividing neighbouring cells. Nuclei in an initial syncytial cell do not divide and an increase in nuclei number results from cell fusion followed by endoreduplication. Cells neighbouring syncytia undergo active mitosis before their incorporation into the NFS. The increase of ploidy levels in nuclei of feeding cells most likely sustains their high metabolic activity needed for the nematode growth and reproduction. Functional analysis using adapted microscopy approaches allowed us to gain insight into the role of core cell cycle components in these intriguing feeding sites. In addition, we describe some imaging methods that were developed to investigate nuclear behaviour and how the cell cycle progress in the complex nematode feeding structures of plant host roots.