The development of specialized fat-and-oil emulsion food systems for the prevention of hyperlipidemia and obesity is an important task of health concern in the Russian Federation. The aim of the study was to develop specialized fat-and-oil emulsion food systems for the prevention of hyperlipidemia and obesity, the distinctive features of which are the presence of functional ingredients and bioactive compounds that meet modern safety requirements, have a hypolipidemic effect and influence on body weight. Material and methods. As a source of fucoxanthin, an oil extract from the thallom (stratum) of the annual Undaria pinnatifida brown algae was used, obtained by re-extraction with soy oil for 8 hours from a glycerin extract (extractant - 60% glycerin solution, the duration of the process - 8 h). The determination of organoleptic parameters was carried out at a temperature of 20 °C 12 h after manufacture using standard methods. Organoleptic parameters were determined in the following sequence: consistency, appearance, color, smell, taste. Physical and chemical characteristics (mass content of fat, moisture, egg products in terms of dry yolk, acidity in terms of acetic acid, emulsion stability), acid and peroxide values were studied by standard methods. Fatty acid analysis of lipids was performed by gas-liquid chromatography. The fucoxanthin content was determined by spectrophotometric method. Results. The presented formulations of lipid compositions as the fat base of specialized oil-fat emulsion food systems for the prevention of hyperlipidemia and obesity included Schizochytrium sp. microalgae oil in a mass fraction of 3-6% as a source of ω-3 polyunsaturated fatty acids (PUFAs) (eicosapentaenoic and docosahexaenoic acids). An oil extract of U. pinnatifida brown algae in a mass fraction of 48-54% was used as a source of fucoxanthin. The total content of PUFA was significantly high - at least 73%, ω-6 PUFA prevailed (48.0-49.1%). However, the high content of ω-3 PUFA (at least 25%) should be also noted. The ratio of ω-3 to ω-6 PUFA was 1:1.72-1:1.90, which is atypical for individual vegetable oils traditionally used as the fat phase in fat-and-oil emulsion systems. The fucoxanthin content in the presented lipid compositions was 6.4-7.2 mg/100 ml. Edible fat-and-oil emulsion food systems for the prevention of hyperlipidemia and obesity (mayonnaise and mayonnaise sauces) with a given ratio of ω-3:ω-6 PUFA containing eicosopentaenoic and docosahexaenoic acids, as well as fucoxanthin, have been obtained. The extract of U. pinnatifida brown algae, containing fucoxanthin, significantly slowed down the processes of lipid oxidation and hydrolysis, as evidenced by changes in the peroxide and acid values of fat isolated from specialized fat-and-oil emulsion systems for the prevention of hyperlipidemia and obesity. Conclusion. Specialized fat-and-oil emulsion food systems for the prevention of hyperlipidemia and obesity (mayonnaise and mayonnaise sauces with different oil phase content), containing fucoxanthin, having an optimized fatty acid composition, a given ratio of ω-3:ω-6 PUFA, high content of essential PUFA (eicosopentaenoic and docosohexaenoic acids) are safe food products with traditional organoleptic characteristics and specified physical and chemical parameters.