A great dilemma that has been coming on and on along time is the data confi-ont and information concepts. It is also true that this confront, in 15 or 20 years ago, was nothing else but pure philosophical thinking, because the market as a whole didn’t have the dimensions neither the technology that were presented in the beginning of this century. A new time that has come, with the new globalized economy, will be the century of the competence and excellence of the institutions’ administrator. Only the companies that know how to work with the correct information will manage the work successfully in full competitive market. We can extract information in abundance from existing day by day data, using a set of techniques that are important and of extreme value in several research areas denominated Data Mining (DM). Our goal here is to get to know better customer and to take competitive advantage in the market, through the combination of knowledge extraction and the concept of Customer Relationship Management (CRM). DM assisting CRM, will provide a series of inferences that one sole technique would not allow us to observe: seek customer’s retention, avoid chum, making loyalty a customer’s commitment.