A fully-monolithic 5 GHz CMOS LC-VCO fabricated in 0.25-μm IP5M CMOS technology is presented in this paper. The tuning range of the VCO is from 4.82 GHz to 6.288 GHz, about 26.4%. The measured phase noise of 4.82 GHz is -119dBc/Hz at 1 MHz offset from the carrier. It meets the requirements for IEEE 802.11a WLAN standard. The current dissipation of the VCO is 4.92-mA from the 2.5 V power supply. In this paper, the on-chip two-turn octagon spiral inductor and on-chip bias-Ts are presented.