We present a case of reconstruction with osteocutaneous radial forearm flap with calcium phosphate cement (CPC) paste to compensate for insufficient amount of radial bone. A 61 year-old female had suffered a left gingival tumor. The tumor was resected with a part of the mandibular bone. A free radial forearm osteocutaneous flap was harvested with a bone segment. After the radial bone was fixed with titanium microplates to create smooth alveolar ridge and the space between the residual mandibular and grafted radial bone was filled with 2cc of CPC. The radial bone and CPC was covered with flap skin. The X-P findings at the 12th postoperative month revealed that a good contour to the alveolar ridge and the CPC-injected space was filled with a uniform, high-density mass without significant volume reduction of the injected cement. The patient was able to wear a partial dental prosthesis successfully, and was satisfied with the result. We conclude that the combined application of radial forearm osteocutaneous flap with CPC is a useful reconstructive option in the selective case with olomandibular defect.