A low power, full integrated 2.4GHz LC resonator voltage controlled oscillator (VCO) using 0.25μm single-poly five-metal CMOS standard process for 2.4GHz ISM band wireless communication application is presented. Low power and low phase noise have been achieved simultaneously by using the cross-coupled transistor topology. The output frequency of the VCO is from 2.210 to 2.484 GHz with a 274 MHz tuning range and the phase noise at 600 kHz offset from the center frequency is -105dBc/Hz. The power consumption of the VCO including buffer amplifiers is 7mA from a 2.5V supply and the output power is -7.55dBm. The chip area is 0.58×0.60mm (excluding pads).