Root-knot nematodes (RKNs) (Nematoda: Meloidogynidae) are one of the major pests of the vegetables causing losses in crop production by forming knots on the roots. RKNs are generally seen in the greenhouse vegetable production areas of the coastal regions of Turkey. Because of commercial nematicides are highly toxic to environment and human health, alternative control strategies are needed. One of effective and environmental friendly methods is using entomopathogen fungi (EPFs) against nematodes. In this study, a potential biological control agents, Turkish isolate of EPF, Purpureocillium lilacinum TR1 (syn: Paecilomyces lilacinus (Thom) Luangsa-ard, Houbraken, Hywel-Jones & Samson) (Hypocreales: Ophiocordycipitaceae) was evaluated to control three species [Meloidogyne arenaria (Neal) Chitwood, M. incognita (Kofoid & White) Chitwood and M. javanica (Treub) Chitwood] of RKNs. Experiments were conducted in plastic pots, 1000 J2s and 3000 eegs of RKNs were applied to 2 cm deep holes in the pots. The serial dilutions of P. lilacinum conidia were prepared 10(6), 10(7) and 10(8) cfu ml(-1) concentrations under haemocytometer. The two controls were pots with RKN eggs or J2s (positive control), and no RKNs (negative control). Bioassays were replicated (pots) five times for each treatment. Total number of egg masses for each plant, plant height, fresh and dry weight of the upper parts of plants and fresh and dry root weight were recorded. Numbers of nematodes were decreased by increasing the inoculum level of the entomopatogenic fungi. 10(8) cfu concentrations of Purpureocillium lilacinum TR1 were found more effective then other concentrations applied.