In trying to bring about online CRM(customer relationship management), companies have paid much attention to eCRM. The key of eCRM is a recommendation system, which is being used by E-commerce sites to find products to purchase. To maintain a constant flow of marketing information and feedback it is important to staying in touch with customers. In this respect, eCRM becomes a serious business tool for sales activities. In this article we present tee case of Kookmin Internet banking eCRM welch is one of the first examples of implementing eCRM in commercial web site in Korea. We examine how Kookmin Internet banking develops eCRM and how it provides customized services to customers. We also explore the role of eCRM in Internet banking and the level of personalization technology used in Kookmin eCRM case.