This chapter presents the Plan-Do-Check-Act (PDCA), a lean manufacturing tool. It includes the concept, origins, and evolution of this tool, its implementation process, and the benefits, critical success factors, and barriers to its implementation. In addition, a bibliometric review of PDCA cycle implementation is presented, highlighting the authors, countries, and institutions that have published the most or are most cited. Finally, a case study on inventory management in a warehouse is presented to demonstrate the benefits of PDCA. In this case, a company presents problems of duplication of product keys and lack of stock, which causes the misdelivery of customer orders. This results in financial losses to the company. To solve this problem, we used the PDCA cycle to create a system for identifying and unifying product keys in a warehouse area to avoid losses generated by the inconvenience of erroneous keys. The results showed improvements in inventory management, which resulted in savings of $180,435.49 MXN. The information in this chapter will assist companies in successfully implementing the PDCA cycle.