Two field experiments were carried out during the two successive summer seasons 2003 and 2004 in Borg Nor El-Homse village; Aga district (31^° 03^-, 31^° 23^- and 7 m); Dakahlia Governorate, Egypt, to study the effect of potassium and zinc fertilization on the plant growth, yield, chemical constituents of sweet potato roots [Ipomoea batatas L. (Lam)] Abees cultivar. Potassium fertilizer rates (0, 48 and 96 kg K₂O fed^-1) as potassium sulphate (48% K₂O) were arranged in main plots, while foliar application doses of zinc (0, 0.1 and 0.2% Zn fed^-1) as zinc sulphate (26% Zn) were subjected in sub-main plots. The studied treatments were in split plot design with three replicates. The growth parameters (plant height, leaves number, stems number, chlorophyll content and leaf area), yield and yield component, chemical composition and nutrients contents and tuber quality were determined in both seasons. The increases in growth parameter, resulting from potassium application, were not significant in both seasons except tuber dry matter in the 1^st season as well as plant height and vine dry matter in the 2^nd season. Spraying sweet potato with zinc sulphate at a rate of 0.2% increased significantly most growth parameter. The data obtained revealed that the highest yield of sweet potato tubers and high tubers quality were obtained from the interactions between potassium fertilization at 48 kg K₂O fed^-1 and zinc foliar application at a rate of 0.2%.