This paper presents an intelligent virtual environment, called AdapTIVE (Adaptive Three-dimensional Intelligent and Virtual Environment), which has its structure and presentation customized according to users? interests and preferences (represented in a user model) and in accordance with insertion and removal of contents in this environment. An automatic content categorization process is applied to create content models, used in the spatial organization of the contents in the environment. An intelligent agent assists users during navigation in the environment and retrieval of relevant information. This is a promising approach for new and advanced forms of education, entertainment and e-commerce. In order to validate our approach, a case study of an e-commerce environment is presented.