BACKGROUND The femur has a complex shape with marked individual differences. The aim of our study was to investigate the anatomy of the femur in normal subjects using computed tomography imaging with the aim of building a digital database of human femoral anatomy. METHODS We studied age- and sex-related variation in the shape of the femur in 169 normal subjects (80 men and 89 women) using Computed Tomography. Subjects were divided into three age groups (Group I: < 35 years; Group II: 36 - 55 years; Group III: > 56 years). Measurements were taken of transverse sections at 25%, 50% and 75% of femoral length. RESULTS The bony surface at the transverse section at 50% of the length of the femur was greater in the older men (p=0.007). There were differences in the medullary canal surface area of the femur at the section at 50% of its length in both women and men (p=0.02). CONCLUSIONS Our study provides a detailed characterization of the anatomical features of the femur of normal subjects, and can be helpful in modelling prosthetic implants or internal fixation devices in relation to the age and sex of the patients.