This study was carried out to investigate Mi allele effectiveness on the tomato resistant reaction to Meloidogyne spp. The plants were cultivated in glasshouse in styrofoam trays in the experimental area of Seeds HortiAgro in Ijaci, MG. The cultivars Rio Grande (susceptible to Meloidogyne spp.) and Nemadoro (resistant Mi/Mi ), were employed in this study. The completely randomized design with 8 replicates and 8 plants per plot was utilized, and the inoculation with Meloidogyne spp. was made at 30 eggs/cm 3 of substrate proportion. The evaluation for number of root-knot, egg masses and eggs, as well as egg mass index, was performed 70 days after the inoculation. The Rio Grande and Nemadoro cultivars were different with regard to M. javanica and races 1, 2, 3 and 4 of M. incognita . The Rio Grande cultivar was susceptible independentely of nematode species or race, and, similarily, the Nemadoro cultivar showed resistante to both M. javanica and M. incognita races 1, 2, 3 and 4. The results confirm the effectiveness of the Mi allele to give resistance to M. javanica and all four races of M. incognita