Ketamine is a non-barbiturate cyclohexamine derivative which produces a state of sedation, immobility, analgesia, amnesia, and dissociation from the environment. One of the most important advantages of ketamine premedication is production of balanced sedation with less respiratory depression and less changes in blood pressure or heart rate. As its effects on intracranial pressure, the possible effect of ketamine on intraocular pressure has been controversial overtime. In this study, we aimed to demostrate all the advantages and possible side effects of ketamine premedication in 100 children with retinablastoma undergoing ophthalmic surgery. All the children were premedicated with ketamine 5 mg kg(-1) 15 minutes before the examination orally and peroperative complications, reaction to intravenous catheter insertion, need for additive dose and intraocular pressures of children were recorded. We showed that ketamine administration orally is a safe and effective way of premedication for oncologic patients undergoing examination under general anaesthesia. The incidence of agitation, anxiety at parental separation and reaction to insertion of intravenous catheter was very low while adverse side effects were seen rarely. Intraocular pressure which is very important for most of the ophthalmic surgery patients remained in normal ranges.