Most companies are overly focused on increasing the number of customers and increasing profits. However, it is very important to understand the fact that attracting customers without a clear strategy of their retention is like fishing with a leaky mesh. It creates the appearance that you managed to catch a lot of fish, but you are left with nothing. The ultimate goal of any business is not just to retain the client, but to make it loyal to its product, brand or service. As the world practice of "fighting" for customer loyalty shows, an increase in the period during which the client is economically loyal to the company is possible only if the company develops toclient positive emotional loyalty. At first glance it seems that emotional loyalty is something ephemeral, not measurable and manageable. However, in practice, customers' emotions can not only be measured, but also directed to the right side for the company. This article will discuss the basic concepts associated with such an indicator as the index of consumer loyalty (NPS). You will learn how a simple poll consisting of one question will help you determine the level of satisfaction of your customers. You will learn how to start using and continue to apply this indicator in your marketing companies.