Abstract: A unitary hollow plastic screw anchor which is capable of being hammered or otherwise driven into a hollow wall, with a weakened separation plane adjacent the entrance portion which is sufficiently strong to hold together during installation in the wall, and sufficiently weak to split apart when a screw is inserted into the installed anchor. Features of the anchor include a generally cross-shaped entrance end for minimal penetration resistance, a generally rectangular interior with arcuate screw centering grooves, a single turn helix adjacent the wall-engaging flange thereof to start the screw, an internal step configuration to accommodate screws of varying diameter, and two longitudinal slots which compress during installation to further reduce penetration resistance.