Abstract: An illuminated locking doorknob apparatus for a door has a door locking set. The door locking set has a knob and lock retaining mechanism that passes through the door. A lock core is removingly and rotatingly secured within the knob and lock retaining mechanism. At least one knob is releasingly secured to the knob and lock retaining mechanism. A keyhole, in the lock core, is accessible through a first port in a wall of the knob. An illumination circuit is within the door locking set. The illumination circuit has a removable DC power source and a removable DC light source in the circuit. The light source is adjacent the keyhole and the light source protrudes through a second port in the wall of the knob to illuminate the keyhole so that a key may be more easily inserted therein. There is a switch in the illumination circuit. The switch has a stationary contact and a sliding contact rod, connected to and actuated by the knob, springingly biased away from the stationary contact.