Background: Endoscopic sinus surgery (ESS) is one of the procedures which need a clear surgical field. The purpose of this study was to compare the effects of propofol and isoflurane on depth of anaesthesia and blood loss during ESS. Materials and Methods: In this clinical trial study, 52 (36 males and 16 females) ESS candidates referred to the Shafa hospital in Kerman. One group received propofol and another group isoflurane. Mean arterial blood pressure (MAP), depth of anaesthesia (DA) and total blood loss were recorded for patients in both groups. Results: DA was decreased in both groups, but no significant correlation was observed between the two groups in DA, MAP and blood loss. Moreover, no significant difference was observed between the two groups in total blood loss. Blood pressure was decreased in both groups during surgery. Conclusion: There is no significant difference between propofol and isoflurane in DA and decreasing blood loss during ESS. Therefore, we suggest the use of hypotensive anaesthetic agents during ESS