A 12 year-old girl with the right thalamic tumor was referred from acute obstructive hydrocephalus and intratumoral hemorrhage. MRI revealed that the tumor showed a iso signal intensity on T1 weighted image, a high signal intensity on T2 weighted image itself, and no Gadolinium enhancement, showing the clear margin. Neuroendoscopic biopsy, the 3rd ventriculostomy, and Ommaya reservoir's placement were performed under general anesthesia for making the histological diagnosis and treatment of obstructive hydrocephalus. The histological diagnosis was anaplastic astrocytoma, Firstly, IMR(interferon β, MCNU, radiation) treatment was tried, but no effect was demonstrated on follow-up MRI. Then, the change from IMR to CARE (carboplatin and etoposide) treatment brought the decrease of the tumor. Thereafter she has been doing well without neurological deficits for 9 months after the surgery. The strategy of treatment for thalamic gliomas was discussed.