This paper aims to study the design of a low-power single-balanced mixer for downconversion in wireless RF receivers. The proposed circuit is designed to work at a radiofrequency of 1.9 GHz using CMOS 0.18 !m technology. The obtained results show a conversion gain equal to 7 dB and low power consumption of 3.86 mW at 1.8.V supply voltage. The single side band noise figure performance was founded to be 8.dB. These results show a good potential of this CMOS mixer and justify its use for low-power wireless communications.