Changes of basic nutrients (dry matter, ash, proteins, dietary fibre, fat, amino acids), vitamins (B1, B2, niacin, pantothenic acid, B6, C, E and carotenoids), minerals and some trace elements (K, Ca, Mg, P, Zn, Fe, Cu and Mn) during germination of common oat (species Auron) and naked oat (species Abel) were followed. Absorption of water caused decrease of dry matter. Content of protein in dry matter increased due the storage starch decomposition in germinating grains. Methionine was found to be the limiting amino acid. After 8 days of germination the fat content was approximately by 7% and 40% lower and dietary fibre content by 212% and 142% higher in naked oat and common oat, respectively (in dry matter). Content of vitamin B2, niacin, pantothenic acid, vitamin B6, vitamin C and carotenoids increased by 429, 282, 188, 172, 447 and 478%, resp. in naked oat. The increase in common oat was even higher, but with regard to lower original levels in dry grain, naked oat represented better source of vitamins. No significant changes were found in vitamin B1, vitamin E content showed slight decrease. Changes of minerals were more favourable in naked oat, increase of Ca, Mg, P, Zn, Fe and Cu between 23.7 and 60.7% of original value was observed. Contents of K and Mn were reduced in both tested oats.