The aim of this study was to investigate the effect of a combination of enamel matrix derivative (EMD) and bovine-derived xenograft (BDX). Intrabony defects were created in dogs and treated with BDX plus EMD, with BDX alone, or with neither (control group). Control group defects were characterized by a long junctional epithelium and little bone formation. The BDX+EMD sites showed a statistically significant increase (P .05) in new bone and cementum formation compared with the BDX-only sites. These findings suggest that the use of BDX with EMD is effective in enhancing new bone and cementum formation and that this combination is effective in the treatment of intrabony defects.