Lean management is a way of thinking and working of the entire system. It is the most effective tool for achieving business excellence, developed in Japan and later applied in the automotive industry. Lean methods have been proven to improve production and organizational performance. Practices are designed to achieve multiple goals within an organization, primarily to improve customer responsiveness through continuous improvement and elimination of all types of activities and processes that do not add value for the customer. Lean is an effective method by which any organization can advance and improve efficiency, effectiveness, productivity and quality. There are numerous tools that have been developed within lean to help with lean implementation. The lean method in production brings significant savings, in terms of both space and time, as well as in workforce efficiency. Lean methodology is used to increase a company's competitiveness, increase product quality, reduce possible costs, improve the overall business system and, consequently, increase value for the customer. In this thesis, the influence of lean on the business of Carel Adriatic Ltd will be presented along with the application of the tools used by the company. For the purpose of the diploma thesis, an interview was conducted, which enabled an insight into the business operations of the company, i.e. the positive and negative effects of lean in the company. In this paper, emphasis is placed on the lean tools and methods that the company uses in its operations. The research results show that the implementation of lean methodology brings numerous advantages to the company: reduction of waste and costs, satisfaction and development of employees, higher quality of work and better competitiveness of the company.