The author discusses and evaluates methods for measuring the level of information asymmetry in enterprises depending on their ownership structure. Information asymmetry is a source of processes such as adverse selection and moral hazard, the author says. An appropriate ownership structure in companies can be used to reduce the negative effects of an information asymmetry. The article examines ways of measuring information asymmetry in terms of the data needed for such measurements and the risk that a given measure will be inaccurate. The author concludes that, in large-scale research, direct measurements of the level of information asymmetry are often impossible and the results must be approximated. When planning research it is necessary to take into account the range of data needed to use a specific measure and the risks related to the inaccuracy of measurements, Kubiak says. When examining the relationship between information asymmetry and a company's ownership structure, researchers should arrange enterprises according to the relative level of information asymmetry, he adds. According to the author, this can be done by developing a composite measure of information asymmetry on the basis of specific indicators using the linear ordering method. Such a procedure should reduce the risk of improper classification of companies according to the level of information asymmetry, Kubiak says.