Postoperative delirium (POD) is a common complication, and the incidence of POD ranges from 10% to 60%. Previous studies suggested that frontal approach and tumor located at the temporal lobe were independent risk factors for POD after supratentorial tumor resections. Therefore, patients undergoing awake craniotomies are high-risk populations for POD. A lot of trials show that dexmedetomidine might help to reduce the incidence of delirium in patients undergoing non-cardiac surgery. However, the impact of dexmedetomidine (DEX) on POD for patients undergoing awake craniotomies remains unclear. The purpose of this study was to investigate the effect of DEX on POD in patients undergoing awake craniotomies.