Two field experiments were conducted at Nubaria region (Behira Governorate), Egypt, during the two successive seasons of 2016/2017 and 2017/2018 to study the response of vegetative growth, yield and quality of cassava crop. Three cassava cultivars (i.e., American, Brazilian and Indonesian cultivar) and three levels of potassium fertilizers (i.e., 75, 150 and 250kg K2Ofed-1) were investigated. The results indicated that, American cassava cultivar recorded the highest vegetative growth, yield and its quality as well as higher chemical composition plants, which were received 250 kg K2Ofed-1. This study also confirmed that the optimum K- nutrition for cassava under sandy soils might support the cultivated cassava plants in their growth, yield and yield quality. This work also could present more details about the suitability of some cassava cultivars to cultivate under sandy soils and drip irrigation and which dose of K-nutrient should be applied. Further investigations are needed to carry out to make a complete program for the fertilization and irrigation of different cassava cultivars under arid conditions in Egypt.