In order to provide the basic data about the hip joint arthroplasty, we measured the femoral head diameter, offset and position in normal 150 males and 150 females using a standardized roentgenographic technique that provided views perpendicular to the plane of the femoral neck in which the focus centered on the lesser trochanter of the femur. We obtained 11.4% of magnification rate by comparing the real size of femoral marker with radiologic size. The result of this study are as following: The mean femoral head diameter was 46.4 ±4.1mm in male and 45.1±3.8mm in female. The mean femoral head offset was 39.2±4.8mm in male and 37.8±4.6mm in female. The mean femoral head position was 48.9±3.2mm in male and 47.6±3.6mm in female.