Two-dimensional ultrasound is a widely used technique for the clinical assessment of carotid atherosclerosis. We measured volumes of atherosclerotic plaques in carotid arteries in 70 patients with a newly developed and tested three-dimensional ultrasound method over a period of twelve months to determine the relation between progression or regression of plaque volume and vascular risk factors. In multiple regression analysis of age, size, smoking, total cholesterol, HDL-cholesterol, HDL/total cholesterol ratio, LDL-cholesterol, triglycerides, HbA1, diastolic and systolic blood pressure, the strongest predictor of plaque progression (p < 0.01) was diastolic blood pressure, diabetes came next (p < 0.05). The optimal adjustment of all risk factors showed a significant influence on plaque progression (r: 0.76).