Abstract Background: The anterior communicating artery (ACoA) is considered the most common site for intracranial aneurysms. The relation between the aneurysm formation and the ACoA complex anatomy is poorly described although it may be one of the most affecting factors in aneurysm incidence. Aim of Study: The aim of this study is to find the correlation between the anatomical variations of the ACoA and develop-ment of ACoA aneurysms, and also to analyze the angiographic differences between them. Patients and Methods: The study group consists of 40 patients diagnosed with ACoA aneurysm and the control group consists of 70 persons, using conventional cerebral angiogra-phy. Results: A strong co-relation was found within the study group between the occurrence of ACoA aneurysm and hypo-plastic A1 segment of the anterior cerebral artery versus the control group (25% vs. 7.14%), also there is also a high incidence of aplastic A1 segment of the anterior cerebral artery versus the control group (12.5% vs. 2.86%). Conclusion: ACoA aneurysm formation is more common with hypoplasia or aplasia of the A1 segment of the anterior cerebral artery.