The development of effective relationships is increasingly recognized as an important component of marketing strategies. Developing and maintaining satisfactory customer relationships can help increase customer retention. From the customer’s perspective, the determinants of relationship satisfaction include factors such as trust, service quality, price perception, inertia, indifference, and switching barriers. The aim of the study is to examine the factors which influence and contribute to customer retention. Mobile industry in Greece was selected to find how customer relationships impact marketing practices in the Greek mobile sector, as well as the effect on customer retention. A questionnaire survey was used to collect the primary data. The author used factor and regression analysis and all tests had a in a 95% confidence level. A statistically significant relationship was found between the dependent variable Customer Retention and the independent variables concerning Price Perception, Inertia, and Customer Satisfaction.