The effect of two isolates of fungi (Glomus mosseae - Trichoderma harzianum); two isolates of bacteria (Azotobacter chroococcum - Pseudomonas fluorescens), and two nematodes (Steinernema feltiae- Diplogaster lheritieri) was evaluated against root knot nematode, Meloidogyne incognita infecting tomato plants under greenhouse conditions. The experiment was conducted in plastic pots (25 cm) at the Research Station of the Faculty of Agriculture in Shebin El-kom, El-Menoufia Governorate. Statistical analysis of the obtained results recorded that predatory nematode, D. lheritieri gave the highest reduction percentage (84.0%) in M. incognita juveniles, as well as it reduced root gall index (60.0%) and mature females (72.3%), compared to the nematicide oxamyl that gave 84.2 & 80.0 %, respectively.  Triple treatment of D. lheritieri + A. chroococcum + G. mosseae was superior recording only 184.7 J₂ / 100 cm³ soil with a reduction percentage of 88.5 % compared to the rest of bio-agents. From the obtained results, it can be recommended to use such treatment which achieved the highest decrease percentages of soil nematodes, number of females and root knot galls compared to oxamyl.