Objective To investigate pre- and postoperative changes of regional cerebral cortical blood flow in patients with cerebral arteriovenous malformation. Method Twenty-two adult patients with arteriovenous malformation( AVM) were recruited into this study at Beijing Tiantan Hospital from September 2001 to May 2002. Eight patients had giant cerebral AVM and the other 14 had a small one. Cortical cerebral blood flow (CBF) was measured by laser Doppler flowmetry ( LDF) before and after AVM resections. After surgery, the probe of LDF was implanted adjacent to the area of AVM and monitored for 24 hours. Results CBF increased significantly after the resection in all patients regardless of AVM size. In patients with small AVM, CBF returned to the baseline level within 4 hours, but in patients with giant AVM, CBF remained high even after 24 hours. Conclusions Monitoring CBF is helpful to understand pre- and postoperative changes of regional cortical CBF in patients with cerebral AVM.