Abstract: A pop-up plunger for selectively closing a generally cylindrical waste drain pipe having a seat at one end and a closure actuator remote from the seat, the plunger comprises a head portion including sealing means for engaging the seat for closing the waste drain pipe. The plunger also includes a support portion which extends from the head portion into the waste drain pipe. The support portion engages the closure actuator for axial displacement of the plunger relative to the waste drain pipe for opening and closing the waste drain pipe and includes guide means projecting into close proximity to the waste drain pipe for guiding the axial displacement of the plunger. The guide means provides at least one drain passage past the plunger to afford communication from the seat to a drain through the waste drain pipe.