The research was based on a 3-year field experiment carried out in south-eastern Poland, in 2013‒2015, on brown, slightly acidic soil. The experiment was established by the randomized subblock method, where the first-order factors were foliar fertilization: (A) Fortis Duotop Zn Mn + Fortis Aminotop, (B) Fortis B Mo + Ferti Agro, (C) Fortis Zn Mn + Fortis B Mo and (0) standard object, without foliar fertilization. The factors of the second order were 4 edible potato cultivars (‘Viviana’, ‘Vineta’, ‘Jelly’ and ‘Agnes’). Foliar application of all fertilizer combinations contributed to the reduction of the content of nitrates and nitrites in potato tubers. However, the response of cultivars to foliar fertilization was varied. The medium late cultivar ‘Jelly’ was characterized by the lowest tendency to accumulate nitrates, while the early cultivar ‘Vineta’ was the highest. The highest content of both nitrates and nitrites in tubers was recorded in the dry year, with a significant shortage of rainfall during the potato growing season, and the lowest in the year, about wet June, and September.