To this day, steel is the most used metal material, and it is used more than ever before. In the 21st century, the use of steel is growing, more than a billion tons are produced annually. According to data from the World Steel Association, the total global production of crude steel in 2022 was 1878 Mt. We define steel as a "green material" because we recycle it more than any other material. The multiple use of "green material" is due to its properties such as elongation, toughness, strength, corrosion resistance and heat resistance etc. It is used in many areas, such as transport (for the construction of bridges, cars, etc.), medicine (surgical instruments), construction industry (profiles, bars, wires), etc. During the production of steel under oxidizing conditions, a large amount of oxygen remains in the steel and it must be reduced in order to eliminate defects in cast semi – finished products. Deoxidation of steel takes place by adding elements that have a high affinity for oxygen, such as aluminum, silicon, calcium, etc. These elements are called deoxidizers and are added to the ladle, and their role is to bind dissolved oxygen in the steel into stable oxides that will later be removed from the steel to a certain extent. In this bachelor thesis, the steel production procedures will be briefly described, the division of steel according to the degree of deoxidation (killed steel, semi – killed steel and rimmed steel), and the procedure and methods of deoxidation. Also, the deoxidation with individual elements will be described and emphasis will be placed on the importance of deoxidation in the production process of quality steel.