Field experiments were conducted at El-Mataana Agricultural Research Station, Agricultural Research Center, Luxor Governorate, Upper Egypt, during 2017/2018 and 2018/2019 wheat growing seasons to study the impact of the infestation by Schizaphis graminum (Rondani) (Hemiptera: Aphididae) on yield and its components on bread wheat cultivar Giza 171. Results indicated that S. graminum infested wheat plants from December, 17^th 2017 to April, 8^th 2018 during the first growing season and from January, 27^th 2019 to April, 13^th 2019 in the second growing season. The total population density of S. graminum during the first growing season (2017/2018) was higher than second growing season (2018/2019). As well, the cumulative counts of S. graminum were 597.00 and 310.33 individuals per season for the two growing seasons, respectively. The means of S. graminum total counts throughout the whole period of two seasons were 35.12 ± 3.31 and 25.86 ± 1.96 individuals per 10 tillers, respectively. Data obtained during both (2017/2018 and 2018/2019) growing seasons revealed that vegetative growth measurements (leaf area, number of spikes/m² and plant height) of the infested wheat plants by S. graminum exhibited smaller rates. Furthermore, three yield parameters i.e., grain, straw and yield (ton/fed) increased obviously of the uninfested plants (control) as compared to those of the infested plants by S. graminum. As for the negative effects on yield components, the infested wheat plants by S. graminum exhibited an obvious decrease in (average number of grains/spike, spike height (cm) and average weight of 1000- grains (gm). As well as, the infested wheat plants showed, significantly, the highest reduction in all studied growth measurements, yield and its components.