Background: Neurosurgical patients are the most critical ICU admissions. While advancements in neurosurgical ICUs (NICU) have improved outcomes of care globally, ICU mortality remains a major clinical issue in developing nations. This study evaluates ICU mortalities of neurosurgical patients in a general ICU setting at the UNIOSUN Teaching Hospital, Osogbo, Nigeria.
 Method: Case records of neurosurgery patients who died in the ICU of UNIOSUN Teaching Hospital, Osogbo, South-Western, Nigeria from June 2012 to May 2022 were reviewed. Simple descriptive statistics of data on demographics, clinical diagnoses, management and outcome were done.
 Results: Mortality rate was 38.9% (84 of 216 admissions). Males were 67(79.8%) and the mean age was 41.5years (Range: 2-85years). The average duration of ICU stay was 3.5days (Range: 30minutes-20days). Most patients had severe traumatic brain injury (TBI) (62, 73.8%). This was followed by cerebrovascular diseases (12, 14.3%) and brain tumours (6, 7.1%). Two had brain abscess. One patient each had mixed subacute/chronic subdural haematoma and severe cervical spondylotic myelopathy. Of the 69 whose case files were found, 7(10.1%) had a diagnosis of brainstem death before eventual 'final' death after an average of 13.5 additional hours on mechanical life support. The identified secondary causes of death included raised ICP, sepsis, primary surgical haemorrhage, seizures, acute kidney injury, malignant hypertension, poor glycaemic control and aggressive blood pressure lowering. Only 1 patient had autopsy.
 Conclusion: Most ICU mortalities among neurosurgical patients were from severe TBI. The establishment of NICU is necessary to improve outcome of care of neurosurgical patients.