The main focus of this work is the cost management of projects carried out by engineering and construction companies (EEC), and proposes models that allow incorporating the generation and analysis of scenarios in their cost control processes. The starting point for this work was the professional experience of the author who, since 2007, works with construction projects planning and control. In this period it became evident to the author how complex and multidisciplinary is to perform the cost management of construction projects. Cost management is an essential task for any economy sector, even more due to the current economic and political environment of Brazil. Given the complexity and importance of the theme, this paper also discusses the importance of adopting a management system by these companies. One of the systems that can be adopted is described in the book A Guide to the Project Management Body of Knowledge (PMBOK® Guide) from Project Management Institute (PMI). The concepts and best practices contained in this guide are increasingly disseminated by various sectors of the economy, including construction. However, this sector has several peculiarities, and many of them directly influence the cost management of the projects. Other concepts and aspects related to the construction sector are also raised, making the discussion on the subject a little more embracing, so that some of these themes may be the object of further studies and research. The proposed tools and models are based on these concepts and are applicable in construction projects cost management throughout their execution. These tools and models can be seen, therefore, as an incremental innovation in the processes adopted by engineering and construction companies, and may be applicable also in other sectors of the economy.