This study was conducted in order to gain an insight into the basic issues of inventory theory and its elementary models. It was carried out by studying available Czech and foreign scientific references, which serve as the basis for mapping the approaches to inventory management as well as research into more complex inventory theory models. The paper deals with the inventory theory itself and describes the formation of quantitative models as tools for optimizing inventory under certain conditions the models have been derived from. The paper also discusses an issue most frequently raised in terms of the inventory theory, i.e. optimization of costs related to the costs of holding stock, which follows the analysis of demand for commodities the selected stock is produced from. Thus, the issues of inventory theory and demand for final product are closely related.