Aim: To study the effects of low doses of ketamine on intracranial pressure in patients having space occupying lesion of the brain. Material and Methods: The present hospital based, observational, experimental study was conducted in the department of neurosurgery operating theatre, Aiims, Patna. 45 patients were patients were divided into 3 groups i.e. Group A, Group B and Group C. Group A was induced with standard induction agents 1-2 μg/ kg of fentanyl, 0.1 mg / Kg vecuronium, 2-3 mg/kg of propofol and 5 ml of normal saline (placebo) through intravenous (IV) route. Group B was induced with 1-2 μg/ kg of fentanyl, 0.1 mg / Kg vecuronium 2-3 mg/kg of propofol and 0.25 mg/kg of ketamine diluted with normal saline in 5ml volume. Group C was induced with 1-2 μg/ kg of fentanyl, 0.1 mg / Kg vecuronium 2-3 mg/kg of propofol and 0.5 mg/kg of ketamine diluted with normal saline in 5ml volume. Results: OSND values varies from 4 to 5.8 mm among all the groups at baseline, with mean of 5.4mm, 5.4mm and 5.3mm among group A, B and C respectively. According to the criteria used in the present study, ICP values decreases approximately similar in group B and C, while it decreased at 2 min in group A and increased again to previous values after 5min. Conclusion: The authors concluded that combined with a benzodiazepine and barbiturates ketamine may be the preferred sedative/anesthetic agent for patients with space occupying lesion, and it can probably be used safely in surgical situations.