During this decade, the complexity of the ASIC design has increased substantially. The need of the ASICs in the wireless, automotive, medical, and other high processing application has grown. The objective of this chapter is to have discussion about the ASICs and the challenges in the ASIC designs. The chapter even discusses the ASIC design flow, process node evolution, and the SOC architecture. This chapter is useful to understand the steps involved in the design of ASIC.