Structuring and phenotyping genetic diversity is an important aspect of the work with breeding sources and materials. In the Introduction, the authors pointed out the role of N.I. Vavilov's scientific foresight in defining the topical trend in researching the genetic diversity of a crop, particularly the analysis of its biochemical composition. As the target of their research, the authors chose biochemical characters identifiable in the process of metabolomic analysis conducted by means of gas chromatography with mass spectrometry. Materials and methods. The object was the grain of naked and covered forms of common oat (Avena sativa L.) from the collection held by the Oat, Rye and Barley Genetic Resources Department of VIR. The analysis of oil fatty acid content and metabolomic research were performed using the method of gas chromatography with mass spectrometry on the chromatograph Agilent 6850 (USA). Results. The obtained metabolomic spectra which reflected the metabolomic status of genotypes of various eco