ABSTRACT                 Wheat leaf rust caused by Puccinia triticina is very destructive to the susceptible wheat (Triticum aestivum L.) cultivars. Breeding for resistance is still the most economic and desirable method for controlling the disease. The objective of this investigation was to: 1) study the nature of inheritance of leaf rust disease resistance as well as grain yield and its related characters, 2) detect leaf rust resistant genes in the studied cultivars under field condition, 3) evaluate using Sequence Characterized Amplified Regions technique (SCAR) for  the leaf rust resistance gene Lr37 and 4) use SCAR as a tool for selecting and pyramiding different Lr's resistance genes in Egyptian cultivars. Combining ability effects were estimated using line × tester matting design. Four high yielding cultivars Giza 168, Sakha 93, Sakha 94 and Gemmeiza 9 as females ( lines) and four leaf rust monogenic lines. i.e., Lr10, Lr19, Lr37 and Lr39 as males (testers). Broad sense heritability (h²b) was computed. The Chi-square test (χ²) was used to test the significant of difference between observed and expected ratios in F₂ populations for leaf rust reaction. PCR reaction for SCAR primers was applied. The study included four characters; plant height (PH), leaf rust resistance as average coefficient of infection (ACI), number of spikes per plant (S/P) and grain yield per plant (GY/P). The obtained results can be summarized as follow; Sakha 93 was the best general combiner for PH and Sakha 94 for leaf rust resistance and GY/P. The best combinations for PH were Giza 168 × Lr39, Sakha93 × Lr19 and Sakha 94 × Lr37; for leaf rust resistance were Sakha 93 × Lr37, Sakha 93 × Lr39, Sakha 94 × Lr10 and  Sakha94 × Lr19 and for yield and its components were Sakha 94 × Lr37 andGemmeiza 9 × Lr19. Giza 168, Sakha 94 and Gemmeiza 9 had one or two genes conferring resistance  to leaf rust. In addition, Lr39 leaf rust resistant gene was present in Giza 168 and Sakha 94. The laboratory studies showed that, the SCAR marker has the potential of detecting Lr37 in the studied Egyptian cultivars as well as the monogenic lines. Moreover, Giza 168, line 1 and line 3 had the leaf rust resistance gene Lr37.