This study was carried out at the El-Kawther Experimental Farm, Faculty of Agriculture, Sohag University, Sohag, Egypt during two successive seasons of 2014/2015 and 2015/2016 to investigate the effect of nitrogen and potassium fertilization on the productivity and quality of four cultivars of potato (Sponta, Brn, Oceana and chara) grown under Sohag Province conditions. Three nitrogen/potassium rates (90N: 48K, 120N:90K and 150N:120K units feddan-1. The obtained results clearly showed that there were significant differences among the four cultivars and the three levels of fertilization among the most of studied characters under this study. The cultivar Chara is the best one on the total yield (9.88 and 10.03 ton/ fed), yield component and most of quality traits. In the case of sowing in the sandy soils under Sohag conditions it was been that the third level (N150:K120) gave the best results. Sponta cultivar was the best on some of the quality traits such as dry matter and starch. Finely the cultivar Chara with the third level of fertilization is the best in the total yield and its components and most of quality traits.