Whey is a by-product of cheese production. Due to the amount in which it is produced, the whey of the dairy industry represents a large burden. It is assumed that almost 50 % of the world's volume is discharged into wastewater, which represents a danger for environmental pollution, and at the same time a valuable resource is lost. One of the ways of its use is the process of anaerobic digestion, which could produce biogas from the by-products. Biogas is a flammable gas whose composition contains methane and carbon dioxide to the greatest extent, and its importance as a cheap and CO2-neutral source of energy stems from the possibility of its use in transport and production of heat and electricity. This research compares the yield of biogas and methane from twelve samples of whey obtained before and after the production of cottage cheese, to which different amounts of citric acid were added. Also, the interdependence of individual samples on parameters such as dry matter content, moisture content, and macro and microelements that affect the quality of the raw material, as well as dependence of biogas yield and chemical oxygen demand. The obtained results showed that larger amounts of citric acid in the sample give a lower yield of biogas, and that the yield of methane in biogas is affected by the quality of the whey. Also, according to the chemical oxygen consumption data obtained in the research, the values found in the whey samples were optimal and the samples with the highest values gave the highest biogas yield.