In the United States, healthcare expenditures and prescription drug costs have been increasing in recent years and policymakers have been interested in slowing down these rising costs. To adequately address rising costs, there needs to be a solid understanding of where the money is going, who is involved, and what role everyone plays. Most people understand that manufacturers produce drugs and pharmacies sell drugs, but they probably are not aware of the existence of many of the other entities involved in the process. These entities play an important role, such as packaging the drugs, negotiating drug formularies, and facilitating payments. This paper identifies the prominent entities involved in the pharmaceutical supply chain and briefly explains their role.