The purpose of this study is to evaluate the regenerative potential of calcium sulfate in the treatment of 2-wall intrabony defects as compared to the flap procedure alone. Periodontal healing of surgically created 2-wall intrabony defects grafted with calcium sulfate were evaluated in dogs. Experimental 2-wall intrabony defects of 4×4×4mm were surgically created in the upper anterior edentulous areas between the canines. The test sites include four 2-wall intrabony defects in 4 dogs treated with a calcium sulfate graft. Another four 2-wall intrabony defects in 4 dogs were treated with flap surgery alone as the control sites. Healing was evaluated after 8 weeks. Apical extention of junctional epithelium(JE) was 2.29mm in the control group and 0.50mm in the test group. The length of connective tissue adhesion(CTA) was 0.53mm in the control group and 1.16mm in the test group. The length of new cementum(NC) was 1.17mm for the control group and 2.55mm for the test group. The length of new bone(NB) was 1.02mm in the control group and 2.27mm for the test group. The test group showed statistically significant differences from the control group in junctional epithelium extension, new cementum and new bone formations (p<0.05). Within the limitations of the present study, the results suggest that calcium sulfate may be a safe and cost-effective bone graft material for the treatment of intrabony periodontal defects.