A case of spontaneous echocardiographic contrast in the left ventricle of a patient with severe aortic insufficiency is presented. This contrast appeared through the mitral valve which opened mainly during tele-diastole. Pulsed Doppler showed the blood flow responsible was laminar and of normal velocity. The mechanism of spontaneous intraventricular contrast cannot be attributed to poor left ventricle function or to high-velocity turbulent flow. We believe that spontaneous contrast was triggered by the decrease in proto-diastolic mitral flow secondary to aortic insufficiency. Transient stagnation of blood in the left atrium might modify the echogenic characteristics of the blood which persist during the passage of the flow through the left ventricle.