The aim of this study was to generate standard curves for bone mineral density (BMD) in a Spanish population using dual-energy X-ray absorptiometry (DXA), at both lumbar spine and femoral neck sites. The total sample size was 2442 subjects of both sexes aged 20-80 years, stratified according to survival rates, demographic distribution by local regions and sex ratio in the Spanish population. Subjects with suspected conditions affecting bone metabolism or receiving any treatment affecting bone mineralization were excluded. The study was carried out in 14 hospitals and bone density measurements were performed, using a QDR/ 1000 Hologic device. In the female population, the highest value for lumbar spine BMD was found within the 30-39 years age group, being significantly lower after the age of 49 years. In the male population, the highest values for lumbar spine BMD are found one decade earlier than in the female population and become significantly lower after the age of 69 years. The highest values for femoral neck BMD in men and women was found in the 20-29 year age group. Values for femoral neck BMD in the female population become statistically lower after the age of 49 years, while in the male population this effect was seen after the age of 69 years. Values for femoral neck BMD were higher in men than women at all ages.