The subject of this paper is the application of the concept of Lean construction in construction companies in the Republic of Croatia. First, based on the available professional and scientific literature, an overview of the theoretical foundations of the Lean concept is given, which when applied in the paper, can affect different types of losses. The development of Lean is described - from Lean thinking, through Lean production and Lean construction, which is a new way of managing construction projects to achieve significant savings. Furthermore, the possibilities of application of Lean construction in construction companies are listed, where the most famous tools/techniques of Lean construction are described, and the obstacles and benefits that have been identified during the application of Lean construction, in construction projects in the world, are highlighted. Also, it was intended to point out the misunderstandings of what constitutes Lean construction, so important correct and incorrect claims about Lean construction were singled out. To investigate the current level of knowledge and application of Lean construction in the Republic of Croatia and achieve the goal of the research, an online survey was conducted in which employees of Croatian construction companies of various sizes and activities participated. Collected information based on the answers of 40 respondents is statistically processed and presented in different relationships and compared with world practice and theoretical foundations of Lean construction.