Foils coated with specific cholesterol esters indicate differences in temperature by changes in color. When these foils are placed on the skin, the skin temperature measured is related to the perfusion provided by the vessels supplying this area of the skin. A group of 300 patients were examined simultaneously with plate thermography and directional Doppler sonography in order to detect obstruction or occlusions of the carotid artery. Abnormalities were found in 42 patients. In 31, the positive findings obtained by the 2 methods were in agreement. In 8 only plate thermography gave a positive result, and in 3 only Doppler sonography yielded a relevant finding. Plate thermography as a method for the detection of a stenosis or an occlusion of the carotid artery is suggested as useful for an initial screening method.