BACKGROUND: Good control of intraocular pressure (IOP) during induction and maintenance of anesthesia is essential for the success of intraocular surgery. Etomidate produces a significant and somewhat greater reduction in IOP than thiopental. This study was designed to compare the effects of etomidate on IOP with those of thiopental in patients receiving succinylcholine, and in whom tracheal intubation was performed. METHODS: Forty ASA physical status I or II patients undergoing elective surgery were divided into thiopental group (n = 20) or etomidate group (n = 20). Intraocular pressure was measured before induction, 1, 2, and 3 minutes after administration of an intravenous induction agent, after administration of succinylcholne, immediately after intubation and 2 minutes after intubation. Systolic blood pressure and heart rate were recorded simultaneously. RESULTS: Both agents produced significant decreases in IOP after administration. At 3 minutes after administration of an agent and after administration of succinylcholine, the IOP of the etomidate group was significantly lower than that of the thiopental group (P< 0.05), but there were no significant differences between the groups in IOP at other stages. CONCLUSIONS: Etomidate is not a more effective intravenous induction agent to control the increase of intraocular pressure following tracheal intubation with succinylcholine than thiopental.