In the article, on the basis of comparative-legal analysis, there is explored the content of concept “commercial secret”, considered the organisational, administrative (management), and legal measures of ensuring the safety of commercial secret, and criteria of referring information to commercial secret. The conditions of ensuring the confidentiality safety of commercial information, the methodology of selecting data constituting commercial secret, and information protection measures are sequentially analysed; the evaluation of the role of administrative information in competitive activity and authorization-based information access system is provided. In the article also the legal nature and kinds of agreements about confidentiality, as well as the content of some of them, measures of protection of commercial secret from disclosure, among which the main place is occupied by liability measures applied on law-breakers, and also basic questions on protection of commercial secret after termination of labour relationship with employee, are studied in details.