This paper describes 2.4-GHz integrated CMOS switch mixer with an integrated transformer and CMOS quadrature voltage-controlled oscillator (VCO) using differential inductors. Also, we describe useful techniques in the CMOS implementation of the switch mixer and quadrature VCO. The fabricated circuits consume about 5.76 mW at a supply voltage of 2.0 V. The CMOS switch mixer has a P1dB of -1 dBm and a conversion gain of -2.9 dB. The phase noise of the VCO is below -109.6 d13c/Hz at 1-MHz offset and 19 % tuning range was obtained.