The fast-increasing issue of antibiotic unavailability or relatively their shortages in the healthcare system has been the point of concern for many countries. With these shortages come unnecessary costs and the need to utilize less optimal treatment thus increasing the risk of antimicrobial resistance and jeopardizing a patient’s health. This thesis is a collaboration with PLATINEA (Platform for Innovation of Existing Antibiotics), aiming to optimize the usage of antibiotics and to increase the availability of important antibiotics in Sweden. To understand the causes that affect antibiotic unavailability, a good view into the antibiotic and pharmaceutical supply chain is important, especially the purchasing systems of it. The complexities in the purchasing system can lead to interruptions in the antibiotics supply chain thus increasing the risk of antibiotic shortages. These shortages in turn increases the risk of antimicrobial resistance, therefore, the purchasing system requires the need to be analysed extensively. This study aims to explore different purchasing systems and conduct cost-benefit analysis of centralized purchasing system in efforts to help reduce shortages of antibiotics in Sweden. This study is based on the existing literature on centralized and decentralized purchasing and also the pharmaceutical supply chain. Qualitative interviews (semi-structured), multiple reports and articles steered the authors in exploring the purchasing systems and mapping the costs and benefits of centralized purchasing. Throughout the research, emphasis was kept on reducing antibiotic shortages. The findings of this study outline the various costs and benefits of a centralized purchasing system and resulted in the implementation recommendation of it over an existing decentralized purchasing system in Sweden.