This report describes color doppler imaging (CDI) in the evaluation and follow-up of nine patients with carotid cavernous sinus fistulas. The orbits and carotid arteries were examined with CDI. In all cases, the diagnosis was confirmed by angiography. CDI clearly demonstrated the dilated superior ophthalmic veins (SOVs) with retrograde flow and low resistance arterial doppler waveform in all nine patients (10 eyes). After the study of quantitative hemodynamics, we found that direct carotid cavernous sinus fistulas showed a high-velocity blood flow in the abnormal SOVs in all seven patients and a very low resistance, high flow volume circulation in the involved internal carotid artery (ICA) in six patients that had been examined; however, two patients with dural cavernous sinus fistulas had a lower blood flow in the SOVs than direct fistulas and no significant hemodynamic changes were found between the ipsilateral ICA and the contralateral ICA. These results were helpful for the diagnosis and the differential diagnosis between direct fistulas and dural fistulas. CDI also provides a convenient way to track the natural history and response to treatment of these arteriovenous fistulas. CDI offer several advantages, namely noninvasive and can be performed easily, quickly, inexpensively and reproducibly.