In this paper, dynamic threshold MOSFET (DTMOS) based down conversion Gilbert mixer is proposed for medical implant communication services (MICS) receiver design using UMC 180 nm CMOS process. The current source helpers and switched biasing technique are used to progress the performance of theDTMOS based Gilbert mixer. The proposed design operates at a radio frequency (RF) of 403 MHz with a maximum conversion gain of 12.5 dB at 5 dBm of LO power. The 1 dB compression point and third order input intercept point (IIP3) for the proposed design is - 8.79 dBm and 3.92 dBm respectively, with a noise figure(NF) of 6.6 dB at an intermediate frequency (IF) of 10 MHz. This design circuit works in 0.9 V supply voltage and consumes a dc power of 0.55 mW with the chip area of 0.035 9 0.037 mm2. So, this design with high conversion gain and better noise performance is a suitable block for MICS applications.