Knowledge is an important resource for successful decision-making process in the whole society today. The special procedures of control and management of knowledge therefore have to be used. In the area of knowledge management and knowledge engineering basic terms of these disciplines are data, information, knowledge and knowledge transformation. The knowledge can be defined as a dynamic human process of justifying personal beliefs. Knowledge is a product of successful decision-making process. Knowledge transformation is a spiralling process of interactions between explicit and tacit knowledge that leads to the new knowledge. Nonaka and all show, that the combination of these two categories makes possible to conceptualise four conversion steps: Socialisation, Externalisation, Combination and Internalisation (SECI model). Another model of knowledge creation is the Knowledge Transformation Continuum (BCI Knowledge Group) that begins with the articulation of a specific instruction representing the best way that a specific task, or series of tasks, should be performed. Knowledge modelling and knowledge representation is an important field of research also in Computer Science and Artificial Intelligence. The definition of knowledge in Artificial Intelligence is a noticeable different, because Artificial Intelligence is typically dealing with formalized knowledge (e.g. ontology). The development of knowledge-based systems was seen as a process of transferring human knowledge to an implemented knowledge base. Decision Support Systems (DSS), Geographical Information Systems (GIS) and Operations Research/Management Science (OR/MS) modelling process support decision-making process, therefore they also produce a new knowledge. A Decision Support Systems are an interactive computer-based systems helping decision makers complete decision process. Geographic Information Systems provide essential marketing and customer intelligence solutions that lead to better business decisions. Operational Research and Management Science (OR/MS) is methodology based on system theory and theory of modelling. The OR/MS models serve for better quantification and precision of decision-making process. In this contribution the role of DSS, GIS and OR/MS models in the process of knowledge creation will be explained. The tacit or explicit character of this knowledge and the process of its creation will be explained and discussed