Assuming that the recommended daily allowance of vitamin D for different groups of the population is from 5 to 15 µg, it appears that a small amount of hot-air dried mushrooms, irradiated with UVB, can supply more than 100% of the daily dose of the compound during whole 18 month storage time. It should be noted that the dried mushrooms before consumption are subjected to different culinary treatments which may lead to losses of vitamin D2. Therefore, it is important that the dried mushrooms contain a relatively high amount of ergocalciferol. Immediately after the drying process vitamin D2 content in 1 g of dried mushrooms was in the case of button mushrooms from 285% to 95% of RDA, in oyster – from 1125% to 375%, and in dried shiitake – from 524% to 174%.