A bridgeless power factor corrector with a single choke is electrically connected to an AC power source. The bridgeless power factor corrector includes a choke element, a first switch, a second switch, a first diode, a second diode, a capacitor, a first rectify diode, and a second rectify diode. The choke element is electrically connected between the first switch and the second switch. The first switch and the second switch are controlled to be turned on or turned off by a first control signal and a second control signal, respectively, to provide a power factor correction for the AC power source when the AC power source is in a positive half cycle or a negative half cycle. Furthermore, a method of operating the bridgeless power factor corrector is provided.