Objective To study changes in neural stem cell proliferation in ischemic brain tissue after cerebral ischemia/reperfusion injury treated with mild hypothermia. Methods The middle cerebral arteries (MCA) of Sprague-Dawley rats were occluded for 2 hours, then reperfused for 3, 7, 11, 14, 18 and 28 days. Using immunohisto-chemical staining, the bromodeoxyur-idine ( BrdU)-positive cells in the brain tissue of the operationally intervened side were examined in a sham-operation group, a control group, and in rats treated using mild hypothermia. Results There were a few BrdU-positive cells in the sham-operated rats, but there were obviously more in the mild hypothermia group than in the control group. The peak period for proliferation of neural stem cells in the ischemic brain tissue was longer in the mild hypothermia group than that in the control group. Conclusion Mild hypothermia may promote proliferation of neural stem cells in ischemic brain tissue after cerebral ischemia/reperfusion injury.