The present study investigates the effects of DFDB graft combined with Calcium sulfate membrane on the periodontal wound healing in dehiscence defects of dogs. Following the initiation of general anesthesia by I.V. administration of 30mg/kg of pentobarbital, first premolar was extracted and full-thickness flap was elevated from the second to the fourth premolar. The portion of premolars coronal to the alveolar crest was removed and mesial and distal roots separated to produce single rooted teeth. Exposed root canals were sealed with Caviton and covered completely with flaps sutured. Following the healing period of 12 weeks, the surgical sites were uncovered and $4{ imes}4mm$ dehiscence defects were surgically created. Those defects with DFDB graft combined with Calcium sulfate membrane following root planing, were designated as test sites and those with flap surgery-only were designated as controls. 1. No foreign-body reaction or inflammation were observed in either groups. Calcium sulfate was completely resorbed in the test sites. 2. Significantly greater amounts of new cementum was observed in test sites compared with the controls. Significant amounts of functionally orientated collagens were observed in the test sites. 3. New bone formation was observed in significantly greater amounts in test sites. The results suggest that combined graft of DFDB and calcium sulfate is extremely biocompatible with a potential for new bone and cementum formation, and functional alignment of periodontal ligaments.