An understanding of the etiological mechanisms is important for therapeutic decisions and prognostic evaluation of patients with ischemic stroke. The object of this study was to evaluate the risk factors, etiological subtypes, and topography of lesion in patients with medullary infarctions (MIs). Besides, we also investigated early neurological deterioration, new vascular events, and functional outcome of all patients at 3-month follow-up. We analyzed our database consisting of patients who were diagnosed with acute MI and who were admitted within 24 hours of onset. Etiological classification of stroke was made on the basis of the Trial of Org 1972 in Acute Stroke Treatment criteria. All of the infarctions were grouped into anteromedial, anterolateral, lateral, and posterior arterial territories and also categorized into those involving the upper, middle, or lower medulla oblongata. Early neurological deterioration, major vascular events within the first 3 months of follow-up and modified Rankin Score at 3 months were reviewed. A total of 65 patients with medullary infarctions were reviewed. Involved arterial territories differed according to the etiological classification. Large artery atherosclerosis was the most common etiological subtype; however, small vessel disease was the most common subtype in medial MIs. The lesions involving the anteromedial territory were common in the upper medullary region, whereas the lesions involving the posterior and lateral territories were common in the lower medulla oblangata. Recurrent stroke was seen in the posterior and lateral territories; however, early progression and poor functional outcome were mostly seen in lesions involving the anteromedial territories.