In recent years, there has been an increasing interest in barley and oats consumption, stemming from a number of positive health effects, which originate primarily from water-soluble dietary fibers (including beta-glucans) and antioxidants. The heterogeneous composition of the cereals grains enables the preparation of milled fractions with various milling and fractionation techniques that contain an increased content of bioactive substances. In master's thesis we tried to obtain flour with different compostition of nutrients and bioactive substances by grinding barley and oats with a stone mill and seperating milled fractions by size. We have also determined soluble and insoluble dietary fiber, proteins, lipids, ash and antioxidants in the obtained barley fractions and confirmed great differences. The majority of the material is represented by small particles, that are rich in starch polysaccharides and contain less dietary fiber and ash than the whole grain flour. Medium sized particles (~20% of the material) are enriched with beta-glucans, with proportions more than doubled relative to the whole grain flour. The largest fractions (~10% of the material) contain a high proportion of antioxidants and ash. A similar distribution in the beta-glucans and ash content was also evident after milling of oats, where the differences between the fractions are less obvious, due to a more coarse grinding. In this work we have shown, that with the relatively simple method of grinding and fractionation of barley and oats, we can obtain flour of various properties and a high added nutritional value.