Mandibular chronic osteomyelitis with diffuse osteosclerosis is recognized as an intractable infectious disease. We emplyed decortication and intra-arterial infusion of antibiotics in 6 cases. Decortication on the affected mandible was performed with retrocatherization to the superficial temporal artery of affected side under general anesthesia. Antibiotics, IPM/CS or FOMX was used through the artery for 4-11 days. In addition, we administered FOMX, PIPC intravenously for 8-17 days. CT and MRI were taken postoperatively. The postoperative follow-up period ranged from 1 year and 6 months to 2 years and 5 months. Postoperative MR showed that bone marrow signal was recovered to approximately normal in 4 cases. High signal area of bone marrow and osteosclerosis image remained in 2 cases, but showed improvement. The results were satisfactory without recurrence in all of 6 cases.