Abstract. Knowledge management is one of the most potent means for the improvement of Lithuanian armed forces efficiency in context of transformations. Knowledge retention is one of the knowledge management processes that is related to knowledge selection, accumulation of the organization experience, renewal of the organizational memory in order to preserve the valuable knowledge from the potential loss. In order for the Lithuanian armed forces to manage the knowledge effectively and develop -it is important to purposefully preserve the valuable knowledge. The knowledge retention management problems of the Lithuanian armed forces are classified into: human, organizational, functional, technological and technical. In order to solve the problematics of such type, the identification of the factors, that provides the premises for the complex assessment of the knowledge retention process, becomes an important factor. The purpose of the article is to identify the factors that are significant for the evaluation of the knowledge retention process effectiveness of the Lithuanian armed forces. In order to achieve the objective such methods as the analysis of the scientific literature, multiple criteria and expert assessment are employed. According to the research results most factors were attributed to the group of the organizational and knowledge content factors.