A calibration circuit (20, 50) and method (60) for calibrating the bias current of a VCO (10, 40) to minimize phase noise. The calibration circuit (20, 50) monitors the average voltage at the common-mode node of the VCO (10, 40) while varying the bias current over a predetermined range. The calibration circuit (20, 50) identifies the bias current associated with the minimum average common-mode voltage and utilizes this bias current for calibrating the biasing transistor of the VCO (10, 40).