Aim: To analyse the effects of low doses of ketamine on intracranial pressure in patients having space occupying lesion of the brain. Material and Method: The present hospital based, observational, experimental study was conducted in the Department of Anaesthesiology & Critical Care in Sher - i - Kashmir Institute of Medical Sciences. This study includes all patients undergoing neurosurgery for space occupying lesion of the brain during the study period. Selected patients were divided into 3 groups i.e. Group A (Placebo), Group B (0.25 mg/kg of ketamine) and Group C (0.5 mg/kg of ketamine). After given of IV drugs all 3 group patients were intubated with appropriate size endotracheal tube, 1% propofol infusion @ 50-200 mcg/kg/hr was stared just after intubation and patients were ventilated with 50% O₂, 50% air for next 5 mins. Results: There was little increase in HR (bpm) among the three groups after post-tracheal intubation at two and five minutes. 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: In patients with space occupying lesion undergoing mechanical ventilation, ketamine effectively decreased ICP and prevented untoward ICP elevations during potentially distressing interventions, without lowering blood pressure.