Inventories are one of the most important factors of any company, no matter in what form and for what purpose they are used. Their main task is to enable the continuous operation of the company. The company must determine the amount of goods, materials, semi-finished or finished products it will keep in stock. This paper tries to show how the amount of inventory affects the work and operations of the company. A large amount of inventory provides security, flexibility, it is easier to resolve differences in demand and supply, it responds to seasonal demand for a certain product, distribution costs are reduced, production costs and the switching of customers to competitors are reduced to a minimum, but larger inventories create higher inventory holding costs. On the other hand, lower inventory levels reduce inventory holding costs, but increase the risks of production stoppages due to insufficient inventory. The paper aims to show how companies plan inventory, what systems they use, and how they manage and classify inventory. In order to solve this problem more easily, the company uses various traditional and modern methods of planning, production and procurement of goods or the application of a just-in-time system in inventory planning. Easier inventory management is made possible by inventory classification, where ABC analysis, XYZ analysis, and combined ABC and XYZ analysis can be used. After the theoretical treatment of the topic, there follows a case analysis based on the company Blažič d.o.o., during which stocks are processed, the method of ordering goods and the standardization of stocks, i.e. the types of stocks the company keeps, as well as the costs that arise in the process.