Dense and homogeneous grafted polymer layers were anchored from the melt onto a silicon wafer modified with a macromolecular anchoring layer rich in epoxy functional groups. A monolayer of poly(glycidyl methacrylate) (PGMA), attached to silicon wafers, served as the macromolecular anchoring layer. Carboxylic acid- and anhydride-terminated polystyrenes (PS) of different molecular weights were used for the grafting. The grafted layers did not dewet at elevated temperatures and did not desorb in a good solvent under ultrasonic treatment. Comparison of the results for the grafting to the PGMA primary layer with literature data obtained for the grafting to the epoxysilane monolayer suggested that there were many similarities between these grafting processes. The same major trends were observed. However, the grafting to the PGMA layer was much more effective. We attribute the high efficiency of the PGMA anchoring layer in the grafting reactions to the high mobility of the epoxy reactive groups and formation of an interpenetrating zone at the PS/PGAM interface.