The objective of the investigation study was to determine the content of nutrient components in the whole grain, husk, endosperm, and bran in different cultivars of oats. The content of dry mass, protein, fat, dietary fibre, total carbohydrates, and mineral compounds in the form of ash were measured. The basic chemical composition of the research material was determined using the AOAC standard methods. The investigation results received permit to state that both the whole grain and endosperm are a good source of the protein in the oat cultivars investigated. It was also found that the fat was regularly distributed in the caryopsis, and the similar contents of this component were found both in the whole grain, endosperm, and in the bran. The husk is the best source of carbohydrates, dietary fibre, and mineral components.