The purpose of this article is to define the tasks and competencies of employees necessary to design and use the knowledge management system in the enterprise. The first part contains theoretical considerations regarding such concepts as knowledge, knowledge management, knowledge management system and competencies. Whereas in the second, author's summary of tasks and competencies of the company employees, which provides guidance for managers of companies interested in implementation the concept of knowledge management system, is discussed. Aforementioned enables an earlier creation of the development timetable for the appropriate employee competencies in response to the planned division of tasks associated with the implementation of knowledge management system. The article is based on the practical authors' experience, gained in the field of the KMS design and business consulting to business needs.