Agro- industrial waste is currently causing great interest among scientific community and industry regarding its re-use as s secondary plant raw material for the extraction of valuable components. Among them, plant polysaccharides stand out becouse of their dominant content and numerous tehnological and functional aspects of their application. Accordingly, it is important to develop methods for detailed characterization of carbohydrates in order to optimize exploitation of selected raw materials for that matter. The aim of this study was to determine the yields of basic polysaccharide fractions in selected secondary raw materials by applying a uniforned method of fractional isolation and also to determine the efficinecy of the proposed procedure by monomer composition analysis. In this study six different secondary plant raw materials were used (sugar beet pulp, walnut shell, cocoa bean husk, onion peel, potato peel and pea pod). Using the fractional isolation, the obtained fractions comprised pectic and hemicellulose substances, as well as cellulose. Pectic fraction showed typical monomer composition and its largest content was determined in sugar beet pulp (18.2% of the dry matter). Walnut shell and pea pod have shown a potential of being a good source of xylan type hemicelluloses (with contents of 28.7% and 22.3% on dry matter basis), while hemicelluloses from other raw materials were extremely heterogeneous. Due to the presence of non-characteristic monomers in some cellulose fractions, applied procedure of fractional isolation requires further optimization, in particular for the raw materials in which the relative content of glucose was less than 80%.