The bachelor thesis focuses on the accumuluation of mercury in a mushroom species – penny bun – Boletus edulis in four sites of Slovakia (Orava – Zázrivá, Žiarska kotlina – Lutila, Horná Nitra – Cígeľ, Horehronie – Bacúch). The site selection was conditional, based on the degree of air pollution and the presence of industrial activity. Mushroom and soil samples were taken in 2020 and analyzed on a single-purpose atomic spectrophotometer AMA 254. The mercury content was determined separately in the caps and stems. Caps showed higher concentrations ranging from 1,978 to 10,850 mg.kg-1 than stems – the range from 1,103 – to 2,889 mg.kg-1. The limit defined by the Food Code of the Slovak republic (0,75 mg.kg-1) was exceeded in all samples. Exceeding limit values were not observed in the soil. The highest concentration has been recorded in Zázrivá locality – 0,142 mg.kg-1.