Isoprostanes are a large group of compounds formed as products of free radical oxidation of polyunsaturated fatty acids, which are isomers of prostaglandin. They are present in all body tissues and biological fluids in quantifiable concentrations. Since 2018, the determination of isoprostanes by chromatographic technique with mass spectrometry is the golden standard of the oxidative stress markers determination in relation to oxidative damage to lipids. The publication is a synthetic review of recently published articles on the use of isoprostanes as a marker of lipid peroxidation determined with the liquid chromatography with tandem mass spectrometry technique. It presents the results of research using isoprostanes as a marker in medicine, in monitoring people working in exposure to harmful substances and in lifestyle research. Med Pr. 2023;74(2):119–25