Abstract: The present toilet light unit has a miniature battery-powered lamp mounted on the top rear of a toilet bowl and controlled by a mercury switch on the toilet seat. The unit has a housing with a battery compartment at the back, a flat bottom wall covered by a self-adhesive layer for engagement with the top of a toilet bowl at the rear, and a depending front end segment which extends around the lamp at the front and sides and has rear edges for engagement with the rear inner edge of the toilet bowl. A socket for the lamp is carried by a holder which is removably attached to the bottom wall of the housing inside its depending front segment. The lamp socket has a terminal projecting up through an opening in the bottom wall of the housing and engaging a cantilevered leaf spring contact which is connected through electrical wiring to the mercury switch.