Genetic nature of stem rust resistance was studied in seven parental wheat cultivars, i.e. Misr-1, Misr-2, Gemmeiza-11, Gemmeiza-12, Shandaweel-1, Giza-171 and Sakha-94 and their F1 and F2 crosses, at Kafr El-Hamam Agricultural Research Station (Sharkyia Governorate), Egypt. Qualitative analysis of the obtained data, showed that the observed ratios, fitted the expected ratios 1:15, 3:13, 9:7, 3:1, 13:3, 1:3 and 7:9 for the aforementioned seven crosses, respectively. Therefore, stem rust resistance in the tested wheat cultivars found to be a simple inherited trait, as it was controlled by only one or two gene pairs in most cases, at adult plant stage. While, quantitative analysis revealed that partial dominance effects being more pronounced in it's genetic expression. Also, the heritability in it's broad-sense was, generally, high (ranged from 79.5 to 96.3%), indicating that the selection for stem rust resistant genotypes in early generations was possible. While, delaying it to the late generations is more effective, due to the importance of dominance effect, in the expression of this trait. Thus, plant breeder should not rely on the host pedigree only, but they should put the pathogen genotype and environment in their considerations, as the two important variables in the pathogen: host: environment systems.