After latent periods lasting from 7 to 23 years, sarcomas of the calvaria developed in four patients who had received radiation therapy for a brain tumor. There was no evidence of bony disease before radiation therapy, and the sarcoma (two fibrosarcomas and two osteosarcomas) developed in the field of radiation in all four patients. One of these four died during resection of the tumor, two survived for either 7 or 21 months after diagnosis of the sarcoma, and one was alive at 23 months after the clinical appearance of the sarcoma. The latter patient has had two resections and extensive chemotherapy. Distant metastases were not present in any of the patients. Sarcoma of the calvarial bones is a serious but rare remote effect of radiation therapy for brain tumors.