Potato cultivars Blaue St. Galler, Valfi, HB Red (with purple- and red-colored flesh), Irga, and Satina (with cream- and yellow-colored flesh) were treated with Trifender WP, Asahi SL, Bio-Algeen S90, and Kelpak SL. The influence of biostimulants on the P, K, Ca, Mg, and Na contents of potato skin and flesh was determined immediately after harvest and after storage. The highest content of Ca in the flesh and skin and the highest content of K in the skin were noted in potatoes treated with Kelpak SL. Potassium content was highest in the flesh of potatoes treated with Trifender WP. Phosphorus content was highest in the skin, whereas Mg content was highest in the flesh of potatoes treated with Bio-Algeen S90. The flesh and skin of cvs. Blaue St. Galler, Valfi, and HB Red were more abundant in macroelements. An increase in the contents of Na and P, and a decrease in the contents of K, Ca, and Mg were observed in the tubers of stored potatoes. The greatest increase in the content of P and Na and the smallest decrease in the concentration of Ca were noted in the flesh and skin of cv. Satina.