Intraocular pressure(IOP) in children is often measured during anesthesia because it is difficult to obtain aedquate cooperation from and awake child. Evaluation of the impact of anesthetic drugs on IOP is imperative for accurate diagnosis and essential in avoiding untoward alterations in IOP during intraocular surgery. IT has been widely believed that IOP is reduced by inhalation anesthetic agenta, but ketamine has been reported to increase IOP have no effect on IOP and to decrease on IOP. WE have investigated the effect of ketamine only, ketamine and halothane, and pentothal sodium and halothane anesthesia on IOP in children. Thirty patients, ranging in age from 5 to 10 years and ASA physical status l to ll, scheduled for elective surgery, were the study group. No patients had glaucoma or corneal laceration. The patients were not premedicated. After instillation of local anesthetic solution into the conjunctival sac, control measurements of IOP were obtained in one eye with a pneumatic Applanation Tonometer(Alcon). The patients were then randomly divided into 4 groups. In group A(10), IOP measurements were recorded for 10 minutes at one minute interval after ketamine 2mg/kg i.v. In group B(10), anesthesia was induced with ketamine 2mg/kg i.v. and succinylcholine 1mg/kg was used to facilitate tracheal intubation. IOP was measured one minute after thiopental and after intubation. Anesthesia was maintained with haothane (1%)-N2O(2L/min)-O2(2L/min) and IOP were measured for 10 minutes at one minute intervals. In group C(10), succinylcholine 1mg/kg given one minute after thiopental 4~5 mg/kg, trachea was intubated following fasciculation and anesthesia was maintained with halothane (1%)-N2O(2L/min)-O2(2L/min). Thereafter IOP was measured for 10 minutes at one minute intervals. All IOP measurements were made by the same examiner using the same instrument. Pulse and blood pressure were simultaneously monitored. The results were as follows: 1) In group : The control value of IOP was 22.1±31 mmHg. Two minutes after ketamine 2mg/kg i.v., mild a increase (2~4mmHg) of IOP was observed and persisted thoroughout the 10 minutes but it was not statistically significant(p>0.05). 2) In group B: After ketamine and succinylcholine, IOP was moderately increased (29.8±3.86mmHg) over the control (24.0±4.09mmHg). AFter intubation, IOP was markedly increased (32.0±4.04mmHg) (p<0.05). Apparently, the elevation in IOP after intubation became reverted and stabilized in 6 minutes to normal or below control level under halothane anesthesia. 3) In group C: The control value of IOP was 20.7±1.11mmHg. It showed that thiopental by itself caused a significant decreased in IOP (17.4±2.87mmHg) (p<0.05). As in B group, IOP increased after succinylcholine(23.0±3.87 mmHg) and intubation(29.4±3.69mmHg)(p<0.05). Elevated IOP lowered and stabilized in 4 minutes after halothane anesthesia.