The subject of the study is the policyholder's duty to disclose to the insurer the circumstances of risk (“duty of disclosure”). The model of information duty of the policyholder, fixed in article 944 of Civil Code of Russian Federation is analyzed, a number of gaps are revealed: deficiency of criteria of the information subject to disclosure; lack of any penalties for the policyholder in case of careless violation of the obligation; lack of differential system of sanctions depending on the degree of policyholder's fault and importance of undisclosed information for the insurer. Based on the study of case law, it is concluded that the courts interpret the provisions of article 944 of Civil Code with a deviation from their literal meaning. When resolving relevant disputes over the invalidity of the insurance contract, the courts take into account the importance of undisclosed information for the insurer (it would have concluded the contract if this information was available), as well as the connection of undisclosed information with the occurrence of the insured event...