This paper reports the design and optimization of a standard cell library in 0.18μm CMOS, together with the analysis on voltage scaling and transistor sizing for ultra-low power biomedical applications. By simulating with a 8-bit 4-tap FIR filter at 0.6V clocked 100kHz, the design achieves 18.6× and 1.55× lower power consumption comparing to a commercial standard cell library working at nominal voltage 1.8V and re-characterized 0.6V. © 2013 IEEE.