In this paper a 2.4GHz CMOS colpitts type microwave oscillator was designed and fabricated using H-spice and Cadence Spetre. There are 140MHz difference between the oscillation frequency and the resonance frequency of a tank circuit of the designed oscillator. The difference is seemed to be due to the parasitic component of the transistor. The inductors used in this design are the spiral inductors proposed in other papers. Cascode current source was used as a bias circuit of a oscillator and the output transistor of the current source is used as the oscillation transistor. A common drain buffer amplifier was used at the output of the oscillator. The measured oscillation frequency and output power of the oscillator are 2.173GHz and -5.53dBm.