Two field trials were conducted during the two fall (nill) seasons of 20032004 and 200412005 on potato cv. Spunta at Beramoon Experimental Farm. Dakahllia Govemorate. for evaluation the effects of foliar spray with seaweed extracts (without. 1gil and 2gll). and inorganic fertilizers (NPK) at levels 50 . 75 and 100 96 of recommended rates fled. (90 kg N+ 37.5 kg P205 + 40 K20. 135 kg N + 56.25 kg P205 + 72 Kg K20. 180 kg N+ 75 P205 + 96 kg K201 fed.) on plant growth. yield and its components. tuber quality as well as chemical constituents. The data were following : Addition of Inorganic fertilizers (NPK) Increased significantly plant height, number of main stemsJr plant in second season. foliage fresh and dry weight. total tuber yield (torv' fed.). number of tubers! plant. tuber weight! plant. tuber dry matter. starch (96). nitrate content (ppm) with increasing NPK level up to 75andior100% cf the recommended rates. as well as NPK contents in leaves at 75 days after planting (BAP). The best growth parameters of potato plant were obtained by foliar application of seaweed extracts at dose (29A) except number of main stems! plant in both seasons and also. increasing total tuber yield (tended). number of tubers! plant. tuber weight! plant. dry matter and starch content while. the lowest nitrate concentration (ppm) in tuber was recorded in the same dose of seaweed as well as increasing NPK content In leaves in the two growing seasons. The interaction between NPK levels and seaweed extracts clear that also. significant effect on plant height. foliage fresh and dry weight, total tuber yield. number of tubers. tuber weight/plant. dry matter. starch content and N in leaves in the first season only. Generally. foliar spraying of seaweed extracts at dual dose (2gfl) in supplying to 75 andi'or 100 % NPK gave the highest yield with best quality of tubers. Moreover. foliar spraying of seaweed extracts alone can make a saving mineral fertilizer contribution due to evoke an effect on plant growth furnishing and yield as well as a wide variety of chemical contents with codified growing environment pollution with high levels of chemical fertilizers.