The effect on microleakage of two glass-ionomer/resin "sandwich" restorations and an incrementally placed microfilled resin restoration was tested in class 5 preparations extending apical to the cementoenamel junction. There was significantly less leakage detected in the sandwich restorations with microfilled resin placed in one or two increments. These results indicate that a glass-ionomer/microfilled resin sandwich restoration may significantly reduce microleakage in restorations extending below the cementoenamel junction.