Whether watershed infarcts and internal junctional infarcts have different mechanisms remains unknown. Of 493 consecutive patients with ischemic stroke or transient ischemic attack, 26 had 1 watershed infarct or more (8 anterior and 21 posterior) and 18 had 1 internal junctional infarct or more. Patients with watershed infarcts were more likely to have arterial hypertension [95% confidence intervals of odds ratio (CIOR): 1.04-6.15] and internal carotid artery stenosis > 50% (95% CIOR: 1.03-7.12) than patients without borderzone infarcts. Patients with internal junctional infarcts were more likely to have heart diseases than patients without borderzone infarcts (95% CIOR: 1.46-10.52). This preliminary study suggests that both subtypes of borderzone infarcts probably have different mechanisms.