Customer relationship management (CRM) systems have always served primarily for the active creation and keeping of long-term beneficial relationships with customers. For CRM, data have always been the alpha and omega. Most of them were put into internal systems manually. However, via big data, it´s possible to process, store, and analyse an enormous amount of data that a customer does not have to even know about, but a company can work with them. Thanks to big data, customer relationship management can become a true help in every company’s business.