Capitalizing on the company’s crucial knowledge is an important operation for company’s success. The first step in knowledge capitalizing is to identify the crucial knowledge for which capitalizing operation is required. The crucial knowledge identification is an ill-structured and multi-criteria problem. In this paper, the crucial knowledge identification problem is structured according to the well-known Simon’s decision making process. Then, a decision support system (DSS), called K-DSS, is developed to support this decision process. The main objectives of this paper are to introduce the crucial knowledge identification decision process, to present the conceptual and functional architectures of K-DSS and to illustrate its utility through a real-world case study conducted in an automobile company.