Background: A head injury is a broad term that describes a vast array of injuries that occur to the scalp, skull, brain, and underlying tissue and blood vessels in the head. Head injuries are also commonly referred to as brain injury or traumatic brain injury (TBI), depending on the extent of the head trauma. Serum electrolyte abnormalities (SEAs) may occur due to the initiation of destructive inflammatory and biochemical cascades of primary brain injury or as a result of interventions such as hyperosmolar therapy. Objective: To evaluate the electrolyte disturbance in patients with head injury in Neuro ICU, Enam Medical College & Hospital, Savar, Dhaka, Bangladesh. Methodology: It was cross sectional observational study carried out by Department of Neuro ICU, Dhaka during the period of 2017-2021. Total 37 head injury patients were included. Data were collected using a structured questionnaire containing all the variables of interest. Data was processed and analyzed with the help of computer program SPSS for windows version 25. Results: This study shows maximum (45.9%) were 15-35 years. The mean age was 30.97±18.49 years (range 2 years-71 years). Majority (94.6%) were male and only 5.4% were female. Most common head injury were due to road traffic accident (75.7%), followed by fall from height which contributes 56 (18.9%). Among 37 patients 28 (75.7%) patients normal serum sodium level, hyponatremia seen in 7 (18.9%) patients and 2 (5.4%) had hypernatremia. Hypokalemia observed in 21 (56.8%) patients, hyperkalemia in 7 (18.9) patients and 9 (24.3%) patients had normal potassium level. Hypochloremia were present in 21 (56.8%) patients, hyperchloremia in 7 (18.9%) patients and in 9 (24.3%) patients no change in serum chloride. Conclusion: Serum sodium, potassium and chloride abnormalities are common in head injury patients in this study. They are associated with higher risk of mortality and can be expected to occur in patients with abnormalities in specific clinical, radiological and acid-based parameters.