WHEAT leaf rust, caused by the fungus Puccinia triticina Eriks., is a destructive disease found throughout common wheat production areas worldwide. Fifty wheat leaf rust monogenic lines were tested with five of Puccinia triticina pathotypes, i.e. BJPPQ, LQFDS, PHFPG, PTPDN, TRFDJ at four stable temperatures (300C, 250C, 200C and 150C). The wheat monogenic lines viz. Lr 16, Lr 17 and Lr 23 were more resistant at 250C, while these genes were found susceptible at 150C, 200C and 300C to all tested races. Eight monogenic lines, i.e. Lr11, Lr12, Lr13, Lr14a, Lr18, Lr47, Lr50 and Lr68 displayed temperature sensitivity which were completely resistant at 150C and 200C. Lr11, Lr12, Lr13, Lr14a, Lr18, Lr47, Lr50 and Lr68 were completely susceptible at 250C and 30⁰C to all races of Puccinia triticina. Lr 34 showed temperature sensitivity to three of the tested races (LQFDS, PHFPG and PTPDN) which was resistant at 150C and 200C, but was susceptible at 250C and 300C. Genes like Lr1, Lr2a, Lr2b, Lr2c, Lr3ka, Lr3, Lr9, Lr10, Lr14b, Lr15, Lr10+27+31, Lr19, Lr24, Lr28, Lr33, Lr36, Lr39, Lr42, Lr51 and Lr67 were slightly resistant at all temperatures to some races and were susceptible to other races. The other tested monogenic lines were susceptible at all temperatures to all tested races. Further, this study will be helpful to develop resistant cultivars against leaf rust of wheat.