In this paper, a high performance current-mode instrumentation amplifier has been proposed with low noise, low power and high CMRR features. The proposed design can adjust the gain with an external resistor for the processing of various biomedical signals. To reduce the noise of the amplifier, two design methods including PMOS input and lateral pnp BJT input have been implemented to improve the prior arts. To meet the single power supply need, a biomedical voltage level shifter is also proposed for low cost CMOS implementation. Based on the post-layout simulation results, the presented current-mode amplifier achieves high CMRR over 120 dB, power consumption of 61 uW at 1.8-V supply using standard 0.18-um CMOS technology.