Objectives: There exists many embryological steps during the development of intracranial vascular structures. Therefore, the congenital variations and anomalies of these structures are often encountered. For a proper evaluation of cerebrovascular imaging studies it is essential to know the frequencies of these anomalies and variations, their locations and the possible accompanying patologies should be distinguished. We aimed to analyse the frequency of congenital variations and anomalies and their association with intracranial aneurysms by evaluating the cerebral angiographic images. Methods: The cerebral angiograms taken for various reasons in the Radiology Department, Faculty of Medicine, Gaziosmanpasa University, between January 2007 and April 2009, were evaluated in a retrospective fashion. We investigated the association of intracranial aneurysms and congenital variations in addition to the influence of variations on aneurysm formation. A total of 254 cases with intracranial artery variation-anomaly and coexisting intracranial artery aneurysm were included in the study. Results: The most common variation in intracranial arteries was the agenesis or hypoplasia of the A1 segment of anterior cerebral artery. This was followed infundibular dilatation of posterior communicating artery and fetal type posterior cerebral artery. The incidence of aneurysm was 22.5% in patients who had A1 hypoplasia-agenesia and 18.2% in patients who had trifurcation of middle cerebral artery. Conclusion: Flow haemodynamics take an important part in the formation of intracranial saccular aneurysms. The incidence of aneurysm formation increases in congenital anomalies of intracranial vascular structures. It is necessary to explore the relationship between variations and aneurysms in order to understand the haemodynamic factors which take place in the pathogenesis of aneurysms. These ratios lead us to think that the incidence of aneurysms increases in cases which have variations when compared to those which have not.