Two field experiments were conducted during the winter seasons of 2014/2015 and 2015/2016 at ELNobarayaRigion 71km, Alex-Cairo desert road, atChipsy Company farm in Beheira Governorate. This investigation aimed to study the effect of BacilliusCirculans (potassium bio fertilizers)in combination with different rates of mineral potassium on the growth, yield and quality characters. Potassium fertilizer at levels 80 and 100kg/fed. with application of bio- fertilizer gave the highest mean number of branches. It was also equivalent to the application of K fertilizer only at 120 kg/fed, or with application of bio-fertilizer but potassium application at 100 kg/fed, gave the best results ofplantheight equivalent to the application of Kfertilizer only at 120 kg/fed, or with application of bio-fertilizer while. The application of K fertilizer only at 120 kg/fed, or with application of biofertilizer gave the highest mean value of total clorophll. Moreover, potassium application at level 100kg/fed,gave the highest mean value of tuber weight(ton)/fed, average tuber weight(kg) dry matter, specific gravity and accepted potato yield for processingequivalent to the application of k fertilizer only at 120 kg/fed, or with application of biofertilizer. The application of K fertilizer only at 60 kg/fed, or with application of bio-fertilizer gave the highest mean number of tuber. Addition of K fertilizer only at 60 kg/fed, gave the highest mean value of nitrogen concentration in leaves and roots.Application of K fertilizer only at 120 kg/fed, or with application of biofertilizer gave the highest mean value of K concentration in leaves and tuber. Potassium application at 100kg/fed, gave the highest mean value of starch content equivalent to the application of K fertilizer only at 120 kg/fed, or with applicationof biofertilizer. Application of K fertilizer only at 60 kg/fed, gave the highest mean value of total sugar and reducing sugar. The lowest level of chips defects was also found at the level 120 kg K/fed, only or with application of bio-fertilizer. Potassium at 100 kg/fed, with application of bio-fertilizer gave the same effect in the two seasons.