The use of composite resin as a restorative material for Class I and II cavities is becoming more common. The marginal leakage at the proximal cervical margin of Class II composite resin restorations remains a major limitation to the widespread acceptance of this material. Although somewhat controversial, beveling of the cavosurface line angle has been suggested as a way to enhance the bond at the cervical margin that finishes on enamel. The acid-etched appearance of beveled and nonbeveled enamel at the proximal cervical margin of Class II cavities was studied under the scanning electron microscope. The results appear to support the efficacy of the beveling of this margin for Class II composite resin restorations.