A case of intracranial multiple fibrous histiocytom is arising from the dura mater and both lateral ventricles is presented. To the authors' knowledge, this is the ninth case of intracranial fibrous histiocytomas reported in the literature. A 10-year-old girl was admitted with a 6 month history of cerebellar ataxia. Radiological examination including CT scan revealed a large mass in occipito-suboccipital region. On November 1, 1978, subtotal resection of the tumor was performed. Yellowish hard tumor, weighing 195 g had wide attachment to the dura mater, but did not invade the brain tissue. Postoperative CT scan, three months later revealed the other tumors in the left lateral ventricle and in the suprasellar region in addition to the lesion that had been operated on. In the course of hospitalization, the suprasellar tumor enlarged rapidly despite of 60Co radiation therapy, then led her to hypothalamic dysfunction. In January, 1981, she had paraplegia and paresis of the right upper extremity. Spinal lesion at the level of C-5 was presumed, but further examination was not performed because of her poor condition. On February 19, 1981, she expired. Autopsy of the head revealed four independent lesions in both lateral ventricles, the suprasellar region and the residual lesion which had been resected subtotally at the operation, respectively. Entire falx cerebri was invaded continuously by the tumor in occipito-suboccipital area. Microscopically, all tumors were identical in histology and were composed of spindle shaped cells with storiform pattern, foam cells and rare giant cells. Any mitotic figures were not detected. Clinical behavior was aggressive but histological figures suggested fibrous histiocytoma.(ABSTRACT TRUNCATED AT 250 WORDS)