The article is devoted to the study of polysaccharides isolated from the basidiomycete raw material I. hispidus and studying their physical and chemical properties. Water-soluble polysaccharides were isolated from mushroom raw materials by the method of sequential water extraction and the yield was 9.44%. Polysaccharides were separated into neutral fractions by ion exchange chromatography and purified from proteins and peptides. During the separation process, it was determined that the polysaccharide sample consisted of homogeneous polysaccharides, while the carbohydrate content of the purified polysaccharide sample was 99.4%. The carbohydrate composition of polysaccharides was determined, it was found that the polysaccharide consists mainly of glucose residues and contains minor amounts of fructose and rhamnose residues. Molecular weight and molecular weight distribution were determined by size exclusion chromatography. The Mw of the polysaccharide sample obtained was 18.7 kDa, the polydispersity index was 1.3. The results of IR-, 1H- and 13C NMR spectroscopic studies have shown that the polysaccharide, according to its structural characteristics, belongs to the β-glucan type polysaccharide having β-(1,3) and β-(1,6)-glycosidic bounds.