Four isolates of different bacterial genera i.e., Bacillus megaterium, Pseudomonas fluorescens, Azospirillum brasilense and Paenibacillus polymexa in addition to one Trichoderma harzianum isolate were tested either in-vitro or in vivo to determine their antagonistic potential toward root-knot nematodes on eggplants. Results of in vitro studies showed that the highest egg hatching and juveniles mortality percentage of Meloidogyne spp. were recorded with B. megaterium. The lowest egg hatching recorded with the same biocontrol agent B. megaterium, under greenhouse conditions. The highest reduction in nematode characters i.e., numbers of galls, egg masses, females/root system and numbers of J2/250 g soil. was achieved with B. megaterium by 82.9, 84.9, 84.3 and 82.0%, respectively, especially when plant was inoculated one week prior to nematode inoculation. In the contrary the lowest effect was occurred particularly with P. polymexa by 47.0, 52.0, 50.9 and 53.3%, respectively, when bioagents inoculated after 7 days of nematode inoculation compared with those treated with nematode only.