The successful treatment of a large endodontically induced periradicular defect and soft tisseu fenestration by combined endodontic and periodontal therapy is described. Endodontics was performed on the mandibular left central incisor, the apex was resected, and a retrograde amalgam was placed. This defect was thoroughly described and the exposed root surface was planed with curettes. Deminerilized freeze-dried bone allograft and a nonresorbable membrane were placed over the defect and the exposed root surface. The membrane was removed in 6 months and there appeared to be bone regeneration with complete closure of the soft tissue fenestration. Endodontic therapy in combination with guided tissue regeneration ans bone grafting may provide another modality of treatment for endodontically related hard and soft tissue defects.