The paper deals with the aspects of building long-term stable business and raising competitiveness of companies under marketing relationships based on the customer relationship management (CRM) approach. The facilities and advantages of CRM systems are described that apply advanced managerial and information technologies. The principal CRM subsystems and blocks are illustrated and described. On the base of the analysis of successful implementations a methodology and steps of the introduction of CRM systems are offered, with indicating necessary rules and procedures for each step. It is shown that for the implementation of a CRM system to be efficient it is required for the company to be thoroughly prepared, restructuring many business processes, which, in the end, is a prerequisite of its long-term competitive advantage.