Transforming growth $factor-{eta}(TGF-{eta})$is a polypeptide biologic mediator considered to play a role in promoting bone formation in bony defect area. The purpose of this study was to examine the effect of $TGF-{eta}$ to the periodontal regeneration of class III furcation defect in dogs. Classs III furcation defects were surgically created on the third and the fourth premolars bilaterally in the mandibles of eight mongrel dogs. Experimental periodontitis were induced by placing small cotton pellets into the created defects for 3 weeks. Experimental sites were divided into 4 groups according to the treatment modalities: Group I-Surgical debridement only; Group II-allogenic demineralized freeze dried bone grafting; Group III-allogenic demineralized freeze dried bone soaked in $TGF-{eta}(4ng/10{mu}l)$grafting; Group IV-allogenic demineralized freeze dried bone soaked in $TGF-{eta}(20ng/10{mu}l)$ grafting. The animals were sacrificed in the 8th week after periodontal surgery and the decalcified and undecalcified specimens were for histological and histometric examination. Although no significant differences was seen in the length of epitheial growth and connective attachment, group III showed the least apical migration among treatment groups. The amount of bone repair was significantly greater in group III, IV compared to group I and group II. New attachment formation was significantly greater in group III and group IV compared to group I and group II. These results suggest the allogenic demineralized freeze dried bone with $TGF-{eta}$ in class III furcation defect has the potentiality of promoting alveolar bone formation and periodontal regeneration.