Root-knot nematodes are globally considered one of the most common phytonematodes infecting sunflower crops. In this context, current study, treatments were designed to enhancing the effect of biological control against Meloidogyne incognita by Trichoderma harzianum and Bacillus subtilis alone or in combination with antioxidant; ascorbic and salicylic acids. All treatments significantly suppressed root-knot nematode compared to control. Generally, the results indicated that the treatments of mixtures of antioxidants + bioagents showed a better response in suppression of root-knot nematode than the bioagents alone, as mixture of T. harzianum + B. subtilis gave the highest reduction in nematode population (72.3% and 80.0%).While the best synergistic effect was noticed by combination between T. harzianum and salicylic acid (74.9% and 84.9%) during the growing seasons 2018 and 2019,respectively.This positively reflected on the plant health through induction of defense related components (phenolic content and oxidative enzymes).