Inventory control problems often arise in different types of businesses. This article presents a case study of a company dedicated to selling, installing and servicing industrial, commercial and residential air conditioning and heating. The company does not have internal control of its inventories in its product warehouses. In 2022-2023, 3,042 problems related to warehouse management were recorded, with an average of 84.49 problems/month. This caused economic problems, project delays, inadequate delivery times, and the inability to guarantee their quality certification goals in the short term. Therefore, the objective of this study is to reduce these problems significantly. For this purpose, lean manufacturing tools such as 5S, Kaizen, and Kanban are implemented. After implementing the improvement, the company had formats for ordering and returning materials to the warehouses and a database for recording materials. In addition, warehouse problems were reduced to 79, with an average of 26.3 problems/month. This concludes that the application of lean manufacturing tools can have a significant impact on warehouse management.