Analog circuits have been viewed as a voltage dominated type of signal processing. With the advent of CMOS technology, shrinking feature size, and reduction of supply voltage a new class of circuits developed: current-mode circuits. Among current-mode circuits "Translinear circuits" is one of the important and emerging research interests for low power analog designers. It is the practical means of implementing nonlinear signal processing functions. The performance of analog circuits strongly depends upon techniques used to exploit the characteristics of the transistors. In this paper, using exponential current-voltage relationship of MOS transistor when biased in subthreshold-mode, a square-root circuit is proposed. The circuit simulations were carried on TSMC 0.18 micrometer technology using ELDO Simulator.