Abstract: The article examines the corporate culture of telecommunications enterprises in the system of corporate relations. The content of key aspects of its formation and development, the features of influences on the regulation of activities in the modern market of services in the industry are disclosed. The modern market of telecommunications services in Ukraine is analyzed by various segments and indicators. The most important indicators that affect the effectiveness of the activities of telecommunications enterprises in Ukraine are determined. The views of scientists on understanding the importance of corporate culture for the successful functioning of modern enterprises are summarized. The analysis of the corporate culture of telecommunications 164 enterprises in Ukraine in the context of digitalization and information security of the modern economy is carried out using the example of Kyivstar as one of the largest telecommunications enterprises in Ukraine. The elements are assessed, the distinctive features and leading types of corporate culture of telecommunications enterprises are characterized. The role of corporate culture in the system of corporate relations and security of telecommunications enterprises is clarified. The essential features of managing the activities of telecommunications enterprises on the basis of a successfully formed corporate culture are identified. A methodological approach to diagnosing the level of development of corporate culture of telecommunications enterprises is proposed. The prospects for the development of corporate culture and security of telecommunications enterprises are highlighted.