An apparatus and method for determining drowsiness of a driver are provided. The apparatus includes an imaging device that obtains an image of the driver and a controller that determines (e.g., based on the image of the driver) when the driver is in a fatigue state, when the driver is in an eyelid closure state, and when the driver is in a wake-up state. The controller further determines that the driver is in a drowsiness state when after the fatigue state of the driver continues over a predetermined first time interval, the eyelid closure state and the wake-up state of the driver alternately and repetitively occur within a predetermined second time interval.