Although abnormalities in course and geometry (tortuosity, kinking, and coiling) of the internal carotid arteries (ICA) are commonly identified, their etiology and relationship with stroke and stroke risk factors remain unclear This study assessed the clinical and ultrasonographic features of the patients with abnormalities in course and geometry of the ICA. Carotid color duplex ultrasound studies of 345 consecutive patients referred to the Neuroultrasound Lab were prospectively evaluated. Abnormalities in direction and course of the ICA were classified according to the criteria of Weibel-Fields and Metz modified by the authors. Kinking was categorized as mild (> 60 degrees), moderate (30 degrees-60 degrees), and severe (< 30 degrees). Carotid abnormalities (CA) were found in 85/345 (24.6%), 60/85 (70.6%) were female. More CA were seen in females older than 60 y/o (p < 0.001), but there was no gender difference in patients 60 y/o or younger CA were bilateral in 41 patients (48%), but in those with unilateral CA, most were on the left. The most common CA was kinking (71 arteries, 56%), followed by tortuosity (48 arteries, 38%), and coiling (7 arteries, 6%). None of the atherosclerotic vascular diseases or risk factors was associated with CA. Mild atheromatous plaques predominated in patients with CA, but moderate and large plaques were more common in the others (p = 0.001). Maximal systolic velocity at the level of CA was higher in patients with kinking or coiling compared with tortuosity (p = 0.001). Lumen diameter at the level of CA was inversely correlated to the severity of CA (p < 0.001). However, carotid stenosis was equally present in all groups. This study suggests that CA have no clear importance as a stroke risk factor or marker of atherosclerotic vascular disease. Our results suggest that CA do not develop as a consequence of vascular risk factors or atherosclerotic lesions, and they are not related to ischemic stroke, TIA or the presence of carotid stenosis. In women, CA was related with advanced age. It appears that CA frequently identified by color duplex sonography are more of curiosity than a clinically significant finding.