This paper presents a wide band upconverter which consists of an inductance switched voltage control oscillator (VCO) and up-conversion mixer. In order to enhance the oscillating frequency range, the VCO has 3-bit control function with switchable inductance. Therefore, it could offer a wide band local oscillator (LO) signal for the upconverter. Meanwhile, the upconverter employs double balanced Gilbert structure to obtain good LO and RF isolation. The monolithic microwave integrated circuit (MMIC) is realized on 0.18 μm CMOS process. The measured results verify that by using the inductance switched VCO, the converter realizes −3 dB conversion gain in a wide band from 5.25 GHz to 6.55 GHz. The compression point P1dB is −12 dBm and the power consumption is 66 mW.