Most authors agree that arachnoid cyst accounts for about 1 % of all intracranial space-occupying lesions, but this lesion is more frequently found now-a-days as the application of cranial CT becomes more common, your cases of intracranial arachnoid cyst were reported with discussions on its etiolgy, pathogenesis, symptomatology, diagnosis, and treatment.In children, the presenting symptom is hydrocephalic manifestations; while in adults, it is headache with various focal symptoms depending on the locations of the cyst. There are certain indications for surgical therapy but direct excision is the treatment of choice in most cases. Surgical mortality should be seriously considered and not be neglected. No death occurred in our four cases.