We propose a proof-of-concept of a switchable multi-frequency MMIC (monolithic microwave integrated circuit) oscillator device, operating in the 60GHz millimeter wave band, which is implemented in GaAs p-HEMT transistor technology. Oscillators that can switch between two frequencies have been designed, fabricated and evaluated. The oscillator uses a cross-coupled FET topology, combined with a bent asymmetric coplanar stripline for the resonator, and a switched-capacitor for the frequency switching components. The oscillator generates two oscillations at ƒ/2 and ƒ where ƒ is the target frequency of around 60GHz. The switchable oscillator has been demonstrated for the range of frequency from 44GHz to 68.9GHz. Moreover, the designed oscillator exhibits a wide-band negative resistance property that allows fabricating switchable oscillators covering the 50 to 75GHz V-band. An evaluated switchable oscillator delivers -17.09dBm and -13.72dBm output power at 62.45GHz and 64.78GHz, for a supplied power of 40.6mW and 39.1mW, respectively.