Ab s t r a c t. There are a large number of modern approaches to the development and implementation of organizational knowledge management systems, methodologies and models of knowledge management. Each of them has its own peculiarities, advantages, and disadvantages, aimed at supporting the knowledge saving process. At the same time, the question of the knowledge system effectiveness remains unclear, what complicates the decision-making process. The article analyzes modern approaches to assessing the effectiveness of the knowledge management system and the feasibility of its implementation in the project environment. The approaches analyzed, such as Kaplan-Norton's Balanced Scorecard (Kaplan-Norton), Non-material Asset Monitor (K.Sweeb), Skandia Navigator (Edvinsson), etc., can be used as macro indicators to determine the benefits of Knowledge Management System, but these indicators cannot reflect actual benefits gained solely by this system in relation to business processes and organizational project objectives. Thus, the actual scientific task is not only to develop a specific method of quantifying the benefits that the Knowledge Management System provides, but also to create indicators for project implementation evaluation through Knowledge Management System efficiency. The paper objective is to develop a comprehensive method for evaluation of the effectiveness of the Knowledge Management System, taking into account the specifics of project management. The proposed model is a multistage process, which allows increasing the reliability of the final decisions on knowledge management in the project and evaluating the profitability of the system. In addition, the model allows reducing the cost of the project, by simulating the influence of the system elements on project parameters. The proposed model is aimed at optimization (the choice of the best algorithm from several), identification (the definition of a system with the most relevant qualifications to the real object in the given conditions) or decision-making on Knowledge Management System in a project environment. Further research will be aimed at the development of automated tools for implementing the model, which will optimize the use of the model in project-oriented organizations. K e ywor d s : knowledge management; model; efficiency; intellectual capital.