Objective : We present the difference of histopathologic changes of the internal elastic lamina (IEL) and collagen III in the superficial temporal artery (STA) between aneurysmal patients and non-aneurysmal patients. Also, the pathologic data with clinical features by comparative methods to validate the risk factor of the intracranial aneurysm are presented. Methods : Samples of the STA were harvested form 38 patients including aneurysmal and non-aneurysmal patients undergoing craniotomy. Paraffin-embedded sections were examined, using hematoxylin and eosin, van Giebson and mouse anti-collagen III staining techniques. Histopathological observations were ana lysed and correlated with clinical features such as presence of aneurysm, hypertension, age, and sex. Results : Twenty-seven patients had the intracranial aneurysm. Of these 24 patients were 50 years old or older. Nineteen patients had a history of hypertension. Twenty patients were female. Histopathological study demostrated the derangement of IEL and the deficiency of type III collagen were prominent in aneurysmal patients (p < 0.05). Fifty years old or older patients did not show correlation with the deficiency of type III collagen, but with the derangement of IEL (p < 0.05). The female sex was not correlated with the derangement of IEL but with the deficiency of type III collagen (p < 0.05). However, Hypertension was not correlated with these pathologic data. Conclusion : Patients with intracranial aneurysms have severe histopathologic changes of the arterial wall showing the derangement of IEL and the deficiency of type III collagen. In the clinico-pathologic study, the advanced age and female sex were considered as risk factors of the intracranial aneurysm.