A simple system for in vitro dual culture of grapevine (Vitis spp.) plantlets and root-knot nematode (Meloidogyne javanica (Treub) Chitwood) is described. Based on the presence or absence of mature females, or the total number of nematodes in the roots after 36-day co-culture, the system reliably discriminated resistant (cv. Ramsey) and susceptible (cv. Chardonnay) grapevines. The system was sensitive enough to differentiate between infestation levels of cvs Börner and Chardonnay, both susceptible in the in vitro conditions. A modification of the system to use plantlets from rooted petioles has reduced labour and space requirements and would suit mass screening of grapevine genotypes in traditional or genetic engineering-based breeding programmes. In both systems, nematodes in roots of cv. Ramsey tended to be associated with brown tissue and, compared with those in roots of cv. Chardonnay, were more likely to be confined to tips rather than be distributed along the root after co-culture for 11 or 36 days.