APPLICATION of N- fertilizer could improve the performance of wheat cultivars and grain quality but is known to affect the level of rust diseases, with higher N correlated with increased disease severity. The present study was carried out during 2016/2017 and 2017/2018 cropping seasons and aimed to determine the differential responses of the tested wheat cultivars to nitrogen fertilizer rates, to define the best fertilizer rate for agricultural improvement and to determine rust severity in wheat cultivars. Study were also determined compromised five fertilizer rates, i.e. 0, 25, 50, 75 and 100kg N fed-1 and three wheat cultivars, i.e. Gemmeiza 11, Shandaweel 1 and Giza 168. Results showed that the interaction effect between nitrogen levels and wheat cultivars was significant for spikes m-2, grains spike-1 and kernel weight. Gemmeiza 11 with 75kg N fed-1 achieved the highest 1000- kernel weight followed by Giza 168 then Shandaweel 1. For rust severity, Giza 168 and Shandaweel 1 were more resistant to rust diseases followed by Gemmeiza 11. Increased levels of N increased the severity of rust diseases during grain filling. Stripe and leaf rust decreased the yield of the rust-susceptible wheat cultivars. Analysis of agronomic data assured the expected outcomes of a positive association between N application and yield up to a certain level of N application. The study also approved that there are significant positive correlations between N rates and rust severity.