OBJECTIVE: Most of the studies that have described surgical procedures for moyamoya disease(MMD) have had the aim to improve the blood flow mainly in the middle cerebral artery(MCA) territory. The purpose of this study is to clarify the good indications for a multiple burrhole operation to treat MMD. METHODS: With the patient under local anesthesia, burrhole trephination with a diameter of 1.5 to 2cm at 3 to 5cm lateral to the midline was performed in a total of 18 hemispheres during 12 procedures. The burrholes were opened in the frontal lobe at 19 sites in 10 patients and in the parietal lobe at 22 sites in 12 patients. Revascularization through multiple burrholes and arachnoid openings was performed in 12 patients who suffered from MMD. RESULTS: As seen on the follow up angiograms, good revascularization was achieved in 27 of 41 burrholes, and mainly from the middle meningeal artery and then from the superficial temporal artery. The moyamoya vessels were decreased in four patients. The neovascularization covered 68.4% of the frontal lobe and 63.5% of the parietal lobe. Compared with the preoperative 99mTc-HMPAO-SPECT, 6 patients showed improvement of cerebral blood flow on the postoperative 99mTc-HMPAO-SPECT. Transient ischemic attack disappeared in three of the four patients who presented with this symptom, and the preoperative symptoms improved in both of the patients who presented with headache and cerebral infarction. CONCLUSIONS: A multiple burrhole operation is a simple technique. The results of our series suggest that the revascularization obtained for adult MMD patients who underwent a multiple burrhole operation is similar to that obtained with other indirect surgeries, but long term follow up studies are needed.