This paper presents a solution for conceptually modeling the training domain knowledge of computer-assisted instructional environments. Conceptual organization of the training domain knowledge, with learning stages phasing, can constitute a solution to the problem of adapting the instructional system interaction to users with different cognitive style and needs. LEARNING AND INDIVIDUAL COGNITIVE STYLES Correlating the assistance capability of instructional systems with different cognitive styles of potential users has lately become an important study and research subject in the area of computer-assisted instruction. The possibility of personalizing the educational process is the main demand in building computer-assisted learning systems for any form of education, continuous education and professional re-conversion included. In the case of these education forms, the subject of study frequently consists of groups of users; between these users there can be significant differences concerning the training level, age or internal goals pursued through study. Consequently, the way the educational process is approached - the cognitive style - can be extremely different among the users who form the study groups (Nicola 1992, Larmat 1997). When computer-assisted learning systems are used for any of these forms of education, they have to be able to dynamically adapt to the various cognitive necessities and demands of the users, in order to ensure the efficiency of the educational act. Considerable research effort has gone into implementing adaptive (depending on the cognitive style) training systems. A direction pursued by many systems designers is to dynamically build a behavioral-cognitive profile of eac h user. Another trend in implementing adaptive web-based training systems consists of a specific structuring of the content elements included in the Domain Model. This structuring is achieved either from the training phases of the instructional process, or from a hierarchy of clearly stated instructional goals and sub-goals. In both cases, knowledge space browsing is monitored in order to dynamically adjust it whenever the user correctly performs certain acts, or reaches certain stages (La Passardiere and Dufresne, 1992, ). The organization model of the training material, which is tightly connected to the representation of the training domain knowledge, has to allow multiple views (presentations) of the concepts in the training domain (Messing, 1990). Studies of computer-based training systems have shown that if they contain a structural model, they facilitate learning. A network-like model with interconnected knowledge nodes would best reflect the structure-based learning paradigm. Network nodes should contain the description of concepts or of their instances, and the links should contain logical relations between these concepts.