The topic of this undergraduate thesis is ''Improving company process by applying Kaizen''. In the first part of the thesis meaning of Lean is defined and the concept of Lean, and Lean manufacturing is described. After that, the historical development of lean management is shown. The basic terminology and concepts are elaborated, and the basic philosophy of this type of production and management is clarified by describing the five basic principles of Lean management. Also described and explained are the seven types of losses in production and the lean metrics, which help to reduce the losses, are listed. In the third part of the thesis the most important tools of lean management are listed and described. Kaizen tool is described in detail, including its features, characteristics and methodology of its implementation, which is based on the PDCA cycle and carried out using Kaizen workshops. The main part of the thesis focuses on the application of Kaizen in the company in order to improve their work processes. This part was done in the company Feroimpex Ltd., which specializes in manufacturing parts for the automotive, railway and tool industry. Kaizen workshop was carried out, for which the team, consisting of the head of the production departmend, three employees from that department and two students, was assembled. The first part of the workshop was the analysis of the current state of the production process. The analysis revealed the problems present in the process, and then the ideas were developed to improve and solve these problems. Then followed the evaluation of the potential results of the application of the proposed ideas for improvement. The systematization of the results is made with the help of a simple software support developed in Microsoft Excel. In the last part of the paper, a general approach to the application of Kaizen in the company is worked out and the conclusion is given.