This retrospective study was performed to precise indications of emergency CT in a general hospital over a 30 months period. We tried to determine, with help of prior studies, the indications for CT of the brain in the management of acute meningitis, acute headache, and in the management of head injury. In acute meningitis, there is no evidence to recommend CT of the brain before lumbar puncture, except to identify patients at increased risk of cerebral herniation. The imaging study of choice in subarachnoid hemorrhage is non enhanced CT scan. This exam has to be performed in case of acute headache. The CT evaluation of patients with minor head injury remains controversial.