Objective: To determine the prevalence of anatomical variations of the circle of Willis (CoW) andtheir association with cerebrovascular malformations detected on cerebral computed tomographyangiography (CTA). Materials and methods: A descriptive, observational, cross-sectional studywas conducted at a tertiary-care hospital involving a Mexican population. Patients of all ages andboth sexes, with complete medical histories and a cerebral CTA scan, were included. Patientswith incomplete CTA studies or missing data were excluded. Descriptive statistics and the phicoefficient were used to assess the relationship between cerebrovascular malformations andanatomical variations of the CoW. A p value ≤ 0.05 was considered significant. All personal datawere handled with strict confidentiality and used exclusively for research purposes. Results:The sample consisted of 97 patients, with a mean age ...