The normal ovine hearts were scanned in water bath with a 5 MHz mechanical sector transducer. The thickness of the right, left and septal ventricular walls was measured ultrasonographically by electronic cursor and then physically with Vermer's caliber. There was no difference between the ultrasound and physical measurements except for the left ventricular wall where a significant difference was found (P/ 0.05). The ratio of the thickness of left ventricular wall to right ventricular wall to interventricular septum was 2:1:2.