Puccinia triticina Eriks. is a wheat disease of major historical and economic importance worldwide. It is the most widespread of the three types of rusts causing significant yield loss over large geographical areas. Yield losses due to leaf rust may be as high as 30 to 50% in years of severe infections. The use of resistant wheat varieties is the most economical and effective method to control the disease. In Ethiopia, several resistant varieties have been released since 1974 but their resistance has broken down only a few years after release. This is attributed partly due to a lack of efficient screening techniques that targets all the pathogens prevailing in the area. Breeding for host resistance should be pre-emptive or anticipatory in approach so that cultivars to be developed should have adequate level of resistance against the prevailing pathotypes.