1. SummaryPurpose: This research paper provides an overview of the factors affecting customer loyalty. Customer loyalty is now known to be a key factor that can change the customer's decision regarding repurchase of a particular product/service. This research paper discusses relationship marketing, customer loyalty and customer satisfaction as fundamental factors affecting customer retention. Design/Methodology/Approach: The data for this study were collected through a questionnaire distributed to the population of Islamabad and Rawalpindi. The results were obtained by testing the hypothesis with regression. Findings: Research Limitations: The limitation of this article is that the data was collected only for the telecommunications industry. This research can further be carried out in the clothing and consumer goods sector. Keywords: Customer loyalty, Customer loyalty, Customer satisfaction and relationship marketing.2. INTRODUCTIONCustomer loyalty is a very old phenomenon. Companies know that to generate greater revenue they need to retain old customers, the benefit of retaining old customers was that they were loyal to the company (product, service) and would not think of switching . very easily to another product, but with time, the entry of competitors and the removal of barriers to meet global business needs has led to knowledge about customer loyalty. It was well explained by the Pareto model that 80% of the company's revenue was generated through 20% of retained customers and their repurchase, thus proving that it is much more difficult to reach a new customer than to retain an old one. .The purpose of this article is to examine the various factors affecting customer loyalty. Customer loyalty is ...... middle of paper .......N. (2002), “The future of relationship marketing”, Journal of Services Marketing, Vol. 16 No. 7, p. 590-592. Smith, DC, (1996), “The Do it all loyalty program - and its impact on customer retention”, Managing Service Quality, Vol. 6 No.5, pp. 33-37. Stauss, B., Chojnacki, K., Decker, A., Hoffman, F. (2001), “Retention effects of a customer club”, International Journal of Services, Vol. 12 No. 1, pp 7-19.Taylor, SA, Celuch, K., Goodwin, S. (2004), “The importance of brand equity for customer loyalty”, Journal of Product & Brand Management, Vol . 13 No. 4, pp. 217-227. Veloutsou, C., Scotland, G., Tzokas, N. (2002), “Relationship marketing and if…? », European Journal of Marketing, Vol. 36 No.4, pp. 433-449.Venetis, KA and Ghauri, PN, (2004), “Service quality and customer loyalty: building long-term relationships”, Vol. 38 n° 11/12, p.. 1577-1598.