One hundred twenty two patients ahd carotid compression tonography (CCT) followed by bilateral carotid arteriogaraphy. Inthe group (82 patients) which was felt to have significant occlusive disease of internal carotid at the level of carotid bifurcation (smaller than 50 percent stenosis), the CCT showed a 92 per cent correlation with arteriography. Of the group (48 patients) that underwent endarterectomy, there was a 94 per cent correlation with CCT testing. In 40 patients, with normal arteriogram or with less than 50 percent stenotic lesions on arteriography, there was a larger number (25% of patients with a CCT test which appeared to indicate decreased flow. Various reasons for this are discussed. The high correlation of the CCT test and carotid arteriography in the patients with surgically amenable lesions would suggest that the CCT test is a good noninvasive screening technique for the detection of significant occlusive disease of the extracranialcarotid vascular system.