Design of CMOS circuits form an important part for VLSI implementation. Analog circuit synthesis might be the most challenging and time-consumed task, because it does not only consist of topology and layout synthesis but also of component sizing. This paper details the Genetic Algorithm (GA) technique for the optimal design of analog circuits. Analog signal processing finds many applications and widely uses OpAmp based amplifiers, mixers, comparators etc., and filters. In this paper, a two-stage opAmp (Miller Operational Trans-conductance Amplifier (OTA)) is considered for the synthesis that satisfies certain design specifications. Performance has been evaluated with the Simulation Program with Integrated Circuit Emphasis (SPICE) circuit simulator until optimal sizes of the transistors are found.