The purpose of this study was to evaluated the effect of muscle relaxants on the intraocular pressure during balanced anesthesia for intraocular surgery. Forty one patients without history of eye disease in physical status 1 and 2 (adopted by American Society of Anesthesiologist). aged from 17 to 66 years were studied during anesthesia for elective surgery. All were premedicated with 50 mg of meperidine hydrochloride and 0.5mg of atropine sulfate. Before induction of anesthesia intraocular pressure was measured and defined it as control value. Anesthesia was induced with 50mg of meperidine hydrochloride. 5mg/kg of thiopental sodium, and 0.11mg/kg of pancuronium bromide or 0.4mg/kg of d-tubocurarine. Anesthesia was maintained by meperidine hydrochloride, nitrous oxide-oxygen. Subsequent measurements were performed at 5, 10, and 20 minutes, after administration of pancuronium bromide and d-tubocurarine respectively. The results were as follows: 1) There was significant decrease in intraocular pressure after intubation with the administration of pancuronium bromide and d-tubocurarine chloride. 2) Significant decrease in intraocular pressure was observed druing balanced anesthesia with pancuronium bromid or d-tubocurarine.