Cloud-based manufacturing is a computing and service-oriented model developed from existing advanced manufacturing models and enterprise technologies with the support of cloud computing, IOT, and virtualization. In this chapter, various definitions of cloud manufacturing are discussed. New service models other than the existing cloud computing service models are being discussed elaborately. Cloud-based design manufacturing is also being discussed. A comparison of cloud manufacturing and cloud-based design manufacturing is elaborately discussed. Key technologies and challenges in cloud manufacturing are highlighted.