Architecture, Engineering and Construction or generally construction industry has recently been characterized by increased requirements for information and communication technologies and knowledge systems. All participants of a construction project, from architect through contractor to investor require a high level of automatization. This results in pressure and increased demand for the use of knowledge systems that streamline these processes. This research discusses the issue of the knowledgebased system used in architecture, engineering and construction field. The main aim of the research was to analyze knowledge-based systems used in architecture, engineering and construction and find the overview of exploitation level in this construction sector. The research sample includes all significant participants of the construction project from designer to investor. All research samples were tested by statistical tests and all the data coming from the construction project are realized in Slovakia.