Postoperative X-ray irradiation(XRT) was performed in 2 dogs with brain tumor. Each histological diagnosis was astrocytoma(grade I-II) and meningioma. Doses of 40Gy in 10 fractions were delivered to tumor beds over 38 days with a Shimazu orthovoltage unit, 200KVp, 20mA, a I.0Cu+ I.0Al filter. Postoperative XRT inhibited tumor regrowth in each case. Irradiated skin showed pigmentation in case 1 and depigmentation in case 2. Two dogs returned to their owners with increased performance status. In the near future, sterotactic radiation surgery will beapplied.