Root-knot nematodes are globally considered one of the most common phytonematodes infecting tomato crops. In this current study, treatments were designed to enhancing the tomato plant resistance against Meloidogyne incognita, this investigation was conducted by different treatments to reduce root-knot harmful effect on tomato plants. Tomato plants were treated with antioxidants i.e., Selenium (Se) at the concentration of 25 ppm, Vitamin C (VC) at the concentration of 50 ppm and Vitamin E (VE) at the concentration of 50 ppm by irrigation and treated with nematicide Oxineem 24% SL which was added at the rate of 4 L/Fed application method. Generally, the results indicated that treatments of antioxidants showed a significant response in suppression of root-knot nematode. The optimum antioxidant treatment was when irrigating tomato plants with Selenium at 25 ppm 8, 15, 30 and 45 days after inoculation, which decreased all parameters of root-knot nematode compared with control. This positively reflected on the plant health through induction of defense related components. The nematicide Oxineem 24% SL gave the highest reduction in nematode population compared with control. All of treatments were significantly effective in increasing enzyme activities i.e., Catalase, Peroxidase and Polyphenoloxidase which are responsible for defense mechanisms of infected tomato plants. Antioxidative treatments with the used concentrations have a great influencing effect on all growth parameters of tomato plants. Histological modifications in tomato plant roots infected with M. incognita treated with different chemical inducers poorly formed giant cells in the central cylinder were detected in the stellar region with limited hypertrophy or hyperplasia contained less or free of cytoplasm, fewer numbers of nuclei, vacuolated in most instances, and were smaller than those of untreated infected roots.