Abstract: A temporary cover for electrical outlet boxes provides for sealing such boxes during the finishing stages of building construction, for plastering and wallboard work on interior walls and the like. The cover comprises a very thin sheet of continuous, unbroken material having an inwardly extending flange which is sized to frictionally engage the inner surfaces of the walls of the outlet box. The cover is pressed into place in the box opening, and plastering or wallboard joint compound work may be performed without possibility of contaminating the electrical box with plaster, wallboard joint compound, or similar materials, and/or possibly completely filling the box with the subsequent problems of locating the concealed box and/or accessing wiring or other components therein which have been covered by plaster or other material. The cover may be removed easily by an inwardly protruding grip, and may be economically discarded after a single use due to its construction of thin vacuum formed plastic or the like.