PACS are very complicated systems. However, whether an enterprise-wide PACS for large healthcare institutions or a mini-PACS for a small clinic or independent imaging center, all of them have interfaces with multiple imaging modalities, a server, workstations, data storage, and networks to connect these together. Various imaging modalities generate medical images that are transmitted through a network to a server where they are managed and stored. Images are then sent to or accessed by workstations through a network, and the displayed images are interpreted and diagnostic reports are generated by physicians. These images and reports can be accessed and retrieved later by PACS, EHRs, or other information systems through a network or a digital storage medium. In this chapter, we discuss PACS servers and workstation architecture.