Increasing use of surgical magnification for operations in the territory of the anterior choroidal artery (AChA) has created a need for detailed knowledge of their anatomical variations. The aim of the present study is to examine the anatomical variations of the AChAin patients operated via pterional approach.The origin and branching pattern of AChAs were observed intraoperatively in 130 patients who were operated via a pterional approach at our center.AChAs arose from the internal carotid artery (ICA) and distal to the posterior communicating artery (PCoA) at a ratio of 70%, from just distal to the original point of the PCoA in 20%, and from just proximal to the ICA bifurcation in 10% of the patients. In 95 cases, AChAs arose from the inferolateral aspect of the ICA in the posterolateral aspect in 27 and from its lateral part in 8 cases. AChAs were found as a single branch at the origins from ICA in 110 patients, as double in 17 cases and as triple in 3 patients.Recognition of anatomical variations and microvascular relationships of AChA will allow neurosurgeons to construct a better and safer microdissection plan, to save time and can prevent postoperative neurological deficits.