Doppler assessment of the intracranial arteries is one of the most commonly ordered additional tests in neurology. The main purpose of the test is to assess morphology and blood flow in the extracranial segments of the internal carotid arteries as well as vertebral and common carotid arteries. The paper presents a brief literature review on the role of a vascular anomaly known as vertebral artery hypoplasia, in everyday clinical practice. The abnormality is a subject of much controversy, including the definition and consistent criteria for the diagnosis of hypoplastic vertebral artery. In literature, the diameter threshold for vertebral artery is most often defined as 2 mm. However, as pointed out in some studies, there are certain situations when vascular diameter below 3 mm may reduce perfusion in the supplied brain region. Depending on the diagnostic criteria and the study population, the estimated incidence of hypoplastic vertebral artery is 1.9–26.5%. Published studies suggest a possible relationship between a hypoplastic vertebral artery and an increased risk of posterior circulation ischaemia. A similar relationship was also shown for congenital vertebral artery asymmetry of more than 1:1.7. It is beyond doubt that the clinical significance of hypoplastic vertebral artery is additionally conditioned by a number of parameters, such as age and comorbidities. The efficiency of collateral circulation, especially in the posterior communicating arteries that make up the circle of Willis, is another important aspect. Another interesting problem is the potential relationship between vertebral artery hypoplasia and migraine with aura. In conclusion, despite much controversy, it seems that hypoplastic vertebral artery should not be automatically considered a vascular anomaly of no clinical significance for the patient.