In order to gain and sustain a competitive advantage in the global economy, today’s organizations need to effectively manage their knowledge resources. Managing knowledge effectively organizations need to gain a full understanding of the recent level of knowledge management system, to know if is it developed effectively, and what direction should organization choose, and what aspects of management should be strengthened in order to succeed. The importance of knowledge management and knowledge management system development is determined by a number of researches, doctoral theses and scientific publications made in this area. A plenty of works present a huge interest of this topic, and show that there are main controversial questions, the resolving of which is important both for scientists and practicians. The assessment of knowledge management maturity in organization is the most important question. However it was incompletely researched till now. According to Grossman (2006, p. 243), measurement is perhaps the least developed aspect of knowledge management because of the inherent difficulty of measuring something that can not bet seen or touched. Desouza, Awazu (2005, p. 207) state that the discipline of knowledge management currently suffers from lack of reliable metrics, scales, or indicators for gauging how well an organization conducts knowledge management. However evaluation of the maturity of knowledge management is important for several reasons. Metrics could allow organizations to make a holistic assessment of knowledge management activities, and systematically understand the current position of knowledge management. They could help organizations identify areas of strength and weakness, which can be reinforced and improved respectively. They could guide the evolution of organizational change, and allow comparisons or benchmarking with similar efforts of other units or companies. Maturity models are used to evaluate the maturity of organization and its knowledge management system. Maturity models describe the development of an entity over time, with the entity being anything that is of interest. In general, maturity models have the following properties (Klimko 2001): 1) The development of a single entity is simplified and described with a limited number of maturity levels; 2) Levels are characterized by certain requirements, which the entity has to achieve on that level; 3) Levels are ordered sequentially, from an initial level up to an ending level (the latter is the level of perfection); 4) During development, the entity progresses forward from one level to the next. No levels can be skipped. However many of current knowledge management maturity models are criticized because they either expend too much efforts in trying to address technological concerns, or are too vague and offer little in the way of practical assistance or not enough emphasis is placed upon culture and other management issues. These show the need of creation of the effective methodology for the assessment of knowledge management system maturity in organization. This paper aims to analyze the existing knowledge management maturity models, to assess their main elements and to formulate the questions, which should be answered in order to construct the effective diagnostic tool that could help to assess which maturity level the organization is, and what paths of improvements the organization should be considering.