To study the effect of phosphine fumigation treatments (two tablet/ton exposure for 24, 48, 72 hours; four tablet/ton exposure for 24, 48,72 hours; six tablet/ton exposure for 24, 48, 72 hours ) on the vitality of bread wheat grains cv. Giza 171 at different storage periods (fresh grains, 3, 6, and 9 months) using a complete randomized design with three replications at the laboratory of Prof. Dr. Youssef Mohamed Omar,  Plant Protection Department,  Agriculture Faculty, Assiut University during the period from 26 May 2022 to 3 March 2023. Grains of Giza 171 cv. were obtained from the Agronomy Department Farm, Agriculture Faculty, Assiut University. The obtained result showed that the tested storage periods had a highly significant effect on all studied traits. Thus, the maximum mean values of germination power (%), germination percentage (%), roots and shoot length (cm), and seedling dry weight (g) traits were recorded at the begging of storage then a gradual decrease occurred. In addition, treating wheat grains with phosphine at different doses for different periods gained a significant increase in all studied traits compared to the control treatment (without fumigation), while there were no noticeable differences between most of the phosphine treatments themselves were found. Therefore, we suggest under the conditions of this study, wheat grains could be treated with 2 tablets of phosphine for a period of 72 hours to reduce the dose and increase the exposure time which could reduce the harmful effects of excessive doses of phosphine.