The focus of this thesis was on characterizing β-glucans and arabinoxylans in selected Canadian malting barley genotypes, and on investigating the effects of different grain hydration levels during steeping on the content and physicochemical properties of these polysaccharides in malt and wort. The results of the first study revealed that Canadian malting barley genotypes differed not only in the content but also in the fine molecular features and properties of B-glucans and arabinoxylans. In the second study, grain hydration levels showed significant differences in the concentration of B-glucans in malt and wort. The impact of variable grain hydration levels on the concentration of arabinoxylans in malt and wort was less pronounced. Grain hydration levels affected the fine molecular structure and molar mass of β-glucans and arabinoxylans isolated from wort, and showed differences between genotypes. The information generated in this thesis about molecular properties of B-glucans and arabinoxylans may be useful to breeders and end users of Canadian malting barley.