Background. The most important qualities of meat and meat products include tenderness, juiciness and color. Sour meat marinating is a commonly used technique. In the available literature, there are no reports on the use of fermented dairy products (FDP) for meat marinating. The acids contained in FDP can improves the tenderness, taste, flavor, juiciness and color of meat products. The use of lower heat treatment temperature for a long time for cooking meat also positively affects its sensory properties and texture. The aim of the study was to determine the influence of marinating meat in kefir, yoghurt or buttermilk and cooking it sous vide (SV) on its physicochemical properties. Material and methods. Muscle cut into slices (m. longissimus dorsi thoracis) was placed in plastic bags, FDP were added to the meat, and the bags were then vacuum-sealed and refrigerated (4°C/48 h). After this time, one of the samples of each variant was analyzed, and the second was cooked SV (63°C/3 h). In the raw and cooked samples, the following were determined: chemical composition, acidity, redox potential, fat oxidation degree and physical parameters, such as texture (TPA test) and color (CIE Lab). Results. Marinating meat did not affect weight loss during meat storage and heat treatment, nor the moisture and protein content. Meat marinating decreased the pH, but had no effect on the content of fat oxidation products and the reduction potential in raw meat. Marinating meat in buttermilk and yogurt and cooking SV resulted in lowering the fat content and limiting oxidation, increasing the reduction potential, reducing hardness and chewiness and increasing the redness of the samples. Conclusion. Marinating meat, especially in buttermilk or yogurt and cooking SV, improves its texture and color and limits oxidation processes. There was no positive effect of marinating meat in kefir on the parameters tested.