The shape of the proximal femoral endosteal canal is so different with age, sex and individual variation that any one contemporary stem cannot afford adequate fitting for all cases. Therefore the accurate knowledge of variability of proximal femoral canal and its chronological change is essential for the selection of the most adequate stem design and prediction of the fate of stem after hip replacement arthroplasty. Total 300 radiographs of proximlal femur (50 cases for each decade, from 3rd decade to 8th) were reviewed for the chronological anthropometric study of proximal femoral geometry and the below results were obtained. 1. The maximum cortical thickness at isthmic level was observed in the 5th decade (9.8+- 1.5mm), with gradual decreament, after then(8.9+-1.9mm in the 8th decad). 2. The endosteal canal ratio at the isthmic level revealed continuous increament from the 3rd decade (0.38+-0.08 in the 3rd decade, 0.44+-0.08 in the 8th decade). 3. About the canal flare index and the stem space flare index, their maximum values were in the 4th decade(4.5+-0.9 and 3.2+-0.6)and decreased gradually(3.5+-0.6 and 2.5+- 0.5 in the 8th decade).