A new diagnostic method for measuring the leg length and the leg length difference by means of ultrasound is presented. A special device for holding and moving the ultrasound transducer was constructed. The measuring points on the hip, knee and upper ankle can be visualised by means of a 5- or 7.5-MHz linear scanner. The measuring device gives the distance of the points in cm so that the difference correspond to the length of the leg, femur and tibia. Tests conducted on corpes and clinical examples show that ultrasound in combination with our special device is an ideal method for determining the exact lengths of the leg. The ultrasound measuring of the leg length offers a reliable, non invasive and easily performed method. Because ultrasound is not limited by radiation hazards, our technique can be used for clinical screening.