Companies use information technology in order to build lifetime relationship with their customers in a very demanding and competitive environment. It is about a customer oriented system which supports companies’ efforts to satisfy and retain their customer base more effectively than few years ago. At the same time creates friendly and useful prerequisites for customers to transact with companies. This dissertation presents the Customer Relationship Management systems. These systems were created for employees to offer better service quality that leads to sales increase, satisfied customers, and more profits for companies. COSMOTE’s customer care department uses ORACLE’s CRM SIEBEL CALL CENTER 8.1 system with much success. This system will be our leverage to develop the arguments for the explanation and the proof of this thesis questions.