Radiation-induced sarcoma represents an exceptional rarity in the head and neck region. The treatment is surgical excision with negative margins and follow-up. After surgery, reconstruction of the defects can be accomplished either surgically or prosthetically. Implant-retained maxillofacial prostheses may offer an acceptable solution. In this report, a large facial defect resulting from radiation-induced leiomyosarcoma was reconstructed with implant-retained prosthesis. A patient with a large facial defect resulting from tumor surgery presented for reconstructive treatment. The primary tumor was fibrous histiosarcoma. Four years after the patient was treated with surgical resection and subsequent irradiation, leiomyosarcoma was diagnosed in the defect site. Leiomyosarcoma was treated with complete surgical resection, and the defect was reconstructed with implant-retained prosthesis. The patient was evaluated every 6 months. Implants provided secure retention to the prosthesis. The patient was satisfied with the appearance of the prosthesis. At 12 months' examination, functioning implants were successful; however, color fade of the prosthesis was observed. Radiation-induced leiomyosarcoma, which is an uncommon tumor in the head and neck region, was treated by means of large surgical resection. Implant-retained prosthetic rehabilitation of the patient resulted in acceptable functional and cosmetic results, and the patient has resumed social activities.