The authors analysed a series of 200 adult patients admitted to the Department of Neurosurgery, Medical University of Lódź with a diagnosis of acute subdural haematoma (ASDH). 63% of them were surgically treated within the first 4 hours after head injury, the others were operated on 4 to 16 hours after trauma. All patients had GCS below 10 for the whole time period from trauma to surgery. Younger patients 18-30 year old had lower mortality-25%, while patients above 50 revealed 75% mortality. Analysis of operative timing and outcome, no benefit revealed when surgery was performed within first 4 hours. However, the patients operated on later than 4 hours after trauma had smaller midline shift and less pronounced brain contusion. It must be taken into account that some patients who could benefit from early surgery-those with quickly developing haematomas and intracranial hypertension-had no chance to arrive and died in peripheral hospitals. Despite our results we advocate an urgent evacuation of haematoma, as early as possible after trauma. Significant correlation was found between midline shift, cerebral contusion on CT scans and results of surgery. Patients with bigger midline shift or presence of focal cerebral contusion revealed higher mortality and worse outcome than patients with smaller shift and no cerebral contusion visible on CT pictures.