The individual and combined diagnostic accuracy rates for fluid-filled oculoplethysmography and pulsed Doppler ultrasonic imaging in the detection of extracranial carotid artery insufficiency were calculated. Results of the two techniques were compared with those of contrast arteriograms which were available for 109 patients, 210 arteries, for computations of sensitivity and specificity. Sensitivities for oculoplethysmography and ultrasonic imaging were 84 and 87 per cent, while specificities were 87 and 81 per cent, respectively. These values were not significantly, p greater than 0.05, different. Results of oculoplethysmography and ultrasonic imaging agreed in four-fifths of the arteries, producing a sensitivity of 98 per cent and a specificity of 97 per cent. In the remaining arteries, the results of the two tests did not agree, resulting in a sensitivity of 71 per cent and a specificity of 79 per cent. Fluid-filled oculoplethysmography and pulsed Doppler ultrasonic imaging are diagnostic tests of comparable accuracy which, when used together, provide accurate hemodynamic and anatomic information in the diagnosis of extracranial carotid arterial disease.