Intraluminal thrombus adjunct to internal carotid artery plaque is a rare finding on traditional diagnostic imaging. Prompt diagnosis is important as it carries a high risk of recurrent stroke. We describe 2 symptomatic patients with severe stenosis on duplex scanning and internal carotid artery thrombus (ICAT) identified on subsequent computed tomographic angiography. Histology of the surgical specimen confirmed the composition predicted by computed tomography. Computed tomographic angiography can provide accurate diagnosis and characterization of internal carotid thrombus and lead to prompt therapeutic intervention.