Features are considered of changing the profile of very long chain fatty acids (VLCFA) in the barley seedling composition in connection with the impact of two abiotic factors: microwave electromagnetic field (EMF) and drought. Studies were carried out on monthly seedlings of barley grown in a soil mixture of peat and sand under laboratory conditions. The experimental chime included six options: 1) control, without microwave processing, normal humidification; 2) EMF with a power of 0.42 kW, a frequency of 2.45 GHz, with an exposure of 11 seconds, normal humidification; 3) EMF with a power of 0.70 kW, a frequency of 2.45 GHz, with an exposure of 11 IV International Scientific and Practical Conference "Modern S&T Equipments and Problems in Agriculture" 117 seconds, normal humidification; 4-6) the same options, but grown in conditions of water scarcity. The content of VLCFA was determined by mass spectrometry. The combined effect of EMF and water deficiency changes the profile of very long-chain fatty acids, which is expressed in a significant increase in Erucic acid in all variants. The action of EMF of 0.42 kW power during the cultivation of seedlings under normal humidification itself in an increase in the content of Erucic acid by 1.6 times, and of 0.70 kW power-by 1 9 times. Increased content of Arachidic and Behenic fatty acids. Changes in the profile of VLCFA in leaves under the influence of water stress and EMF are associated with the activation of the main adaptive systems in the body of seedlings.