IR-spectra of water-soluble polysaccharides (WSPS) extracted fruits of hawthorn of Meyeri (Сrataegus Meyeri L.) and its derivativesare has been examined. When comparing spectra WSPS and its derivatives it became obvious that carboxylic groups in WSPS exist in the free and ionised condition, as well as carboxylic groups partially methylated . Uronic acids as component of polysaccharide chains have piranose configuration.