The experiments were carried out in the experimental farm of Sakha Agricultural Research Station, Kafr El – Sheikh Government during two successive seasons, 2013/14 and 2014/15. This study was carried out to determine the relationship between rates of N and K Fertilization on the average number of the bird cherry – oat aphid, Rhopalosiphum padiattacking wheat. The obtained results showed that, R. padi population increased significantly by increasing the rate of nitrogen fertilizer (Nitrates 33.5%). the average numbers of R. padion wheat during the twosuccessive seasons .The highest average number of R.  padiwas recorded on nitrogen rates of 200 Kg with an average of 342.5 ±  95.7 and 236.2 ± 56.9indiv.respectively. While, the lowest average number of aphid was recorded on nitrogen rates of 0 Kg with an average of 259.4 ± 79.4and 179.7 ±47.6indiv. respectively. Statistical analysis during the twoseasons indicated significant differences between the aphids' and N rates on wheat. The results indicated that increasing potassium fertilization level from 25 to 75 Kg /fed. Caused a significantly decreasing in the average number of R. padi during the first season while the second season was in significantly. the highest average number of R. padiwas recorded on the first level of potassium fertilization with an average number of 213.2 ± 64.7 and 170.8 ± 52.1indiv.respectively.While, the lowest average number of aphid was recorded on the four level of potassium with an average of 154.1 ± 48.3 and 123.1 ± 36.8indiv.respectively.