We present the literature review describing food, medicinal and ecological properties of the fungus Pleurotus ostreatus (oyster mushroom). It is shown that the mushroom is adequate foodstuff for human beings. It provides with proteins, carbohydrates, fats, vitamins and mineral salts. Protein of the oyster mushrooms’ mycothallus contains 18 amino acids, eight of which were essential (isoleucine, leucine, lysine, methionine, phenylalanine, tryptophan, threonine, and valine). Therapeutic value of the mushroom is characterised by a content of water-soluble (thiamine B1, riboflavin B2, niacin, B5, PP, pyridoxine B6, biotin B7, ascorbic and pantothenic acid) and liposoluble (calciferol, ergosterol, tocopherol) vitamins. The considerable gains from the farm wastes use for the mushrooms raising with subsequent application of the substrate in plant cultivation and animal husbandry are stated.