This chapter presents a comprehensive overview of the concepts of technology scaling and the effects of technology scaling on CMOS analog circuit design. With the advent of nano-scale CMOS technology, complex System-on-Chips are used in almost all the domains of electronic systems such as telecommunications, multimedia, consumer electronics, instrumentation and defense applications. In scaled CMOS technology, several significant effects, referred to as short channel effects of Metal-Oxide Semiconductor (MOS) transistors, play a major role in determining the performances of analog circuits. The thin oxide required for scaled CMOS technologies causes tunneling of the carriers such that the gate current becomes non-negligible. In scaled CMOS technology, as the gate current increases, the current gain reduces and the MOS transistor operates similar to a bipolar device, with performances controlled by the gate current. With the scaling of CMOS technologies, the yield and the reliability of integrated circuits becomes a critical challenge to the designers.