The familial occurrence of brain tumors are exceedingly rare except in cases with phacomatosis. We encountered pituitary adenomas in two sisters of a family, so far presenting no evidence of multiple endocrine adenomatosis (MEA). Case 1, K. O. a 26-year-old woman was admitted to our Hospital on September 10, 1970 with visual acuity and field disturbance, irregular menstruation and acromegaly. Neurological examination: Her visual acuity was Vd 0.6 and Vs 0.3, visual field was bitemporal hemianopsia, and ther was papilledema bilaterally. She had left exophthalmos and left abducens palsy. Roentgenogram of the skull, brain scanning, cerebral angiogram, pneumoencephalogram suggested the presence of a pituitary tumor. On Sep. 17, 1970, through a left frontotemporal craniotomy the tumor was removed subtotally. The pathological diagnosis was pituitary adenoma (chromophobe). Case 2, M. T. a 31-year-old woman, sister of case 1, was admitted to the Hospital on September 19, 1973, with mild headache, left visual field disturbance and amenorrhea. She had a child, and a past history of pulmonary tbc. Neurological examination: Her visual acuity was Vd 1.2 and Vs 0.03, and visual field of the right eye was temporal lower quandrant anopsia. There was optic nerve atrophy in the left eye. Plain X-ray craniogram, brain scanning, cerebral angiogram and pheumoencephalogram suggested the presence of a pituitary tumor. On Sep. 28, 1973, a right frontal craniotomy was performed. The tumor tissue with capsule was removed subtotally. The pathological diagnosis was pituitary adenoma (mixed type). In the literatures about familial brain tumors with histological diagnosis, glioma and glioblastoma are common, meningioma is relatively rare. Pituitary adenoma with no evidence of MEA is exceedingly rare. The two sisters presented in this paper, have no evidence of hyperparathyroidism, pancreas adenoma and peptic ulcer. So, we consider, at present, these cases should not be field in MEA.