One of the fundamental aspects of the big data phenomenon is the possibility of application in management. This potential differs depending on the specifics of the organization and the area of application. The article aims to indicate the specificity and directions of applying big data methods in marketing, with particular emphasis on improving customer relationships. After presenting the general characteristics of the big data phenomenon in management, the evolution of business analytics related to new possibilities of mass data processing was described. Then, the focus was on the examples of big data applications in improving customer relationships, which confirms the thesis that these methods are very useful in marketing.