The histological changes resulted from the infection with  Meloidogyne incognita in root tissues of the susceptible (Meetghamr) and the resistant (Florida) peach rootstocks were studied. In the susceptible rootstock, clusters of numerous typical multinucleated giant cells entirely filled with dense cytoplasm and highly thickened cell walls and relatively larger than those in the resistant rootstock were observed. However, in such resistant rootstock (Florida), although some penetrated stages succeeded to feed normally forming typical giant cells , vacuolated giant cells of moderate thickened cell walls , necrotic areas, hyperplastic cells and, cavities were more frequently observed. Withal, numerous penetrated stages failed to develop to reach maturity.