Many varieties commercial's tomatoes have been grown in Egypt but most of them susceptible to the disease of late blight, which are very important and most dangerous fungal diseases that destroy the tomato crop in all its parts caused by the disease Phytophthora infestans. The L03684 wild tomato genotype was obtained from the Asian Development Center for Vegetables. The  inter specific cross between  L03684 and Edkawi species was done to obtained the six populations and study resistance of Late blight heredity, and assessment of genetic parameter for resistance. Results showed that, Many genes control the heredity of resistance to P. Infestans and resistant is inherited as a quantitative trait. While, susceptibility to late blight is a dominant characteristic of resistance. The heritability in broad (H_b.s%) estimates were 71.8 and in narrow sense (H_n.s %) estimates were 39.35% for severity detect the proportion of the environmental factors on the total variation. the inheritance of resistance to P. infestans greatly affected by dominance gene effects. While that, gene effects of estimations were low. So the effects of gene refers to epistasis more important than the additive. This study showed that, the inter actions between additive and dominance were highly significant in the inheritance of resistance to P. infestans. One of the best methods to breeding to improve this resistance by the reciprocal recurrent selection.