This paper explores the application of lean methodology in project management and analyzes the impact of digital transformation on the industry. The introduction explains the basic principles of lean and identifies various types of waste that can occur in the production process. Subsequently, the paper provides a deeper insight into project management, emphasizing the differences between traditional and modern agile methods, with a particular focus on Lean Project Delivery System (LPDS) model. The paper also details the evolution of industry through three industrial revolutions, with a special focus on the concept of Industry 4.0. Digitalization and digital transformation are essential terms in today's context, and the paper offers a brief overview and interpretation of these concepts, along with certain cost aspects they may entail. The final part of the paper presents an example of managing an internal project within the company Končar D&ST, focused on the internal development of a tailor-made digital system . This section integrates the concepts of lean, digitalization, and project management, offering readers a sort of "cookbook" or inspiration through a concrete example of project implementation in practice. The paper demonstrates how the integration of lean principles and tools within project management can significantly enhance efficiency and competitiveness in project execution, while digital transformation serves as a key factor for further improvement of business processes and outcomes.