Dual photon absorptiometry (DPA) of the lumbar spine (2nd, 3rd and 4th lumbar vertebrae) was carried out using a Norland 2600 bone densitometer on 194 Omani women (OW). The exclusion criteria were (1) any medical treatment known to affect calcium metabolism or bone mass, (2) osteomalacia or secondary osteoporosis, (3) the presence of osteophytes or compression fractures of the lumbar vertebrae and (4) the presence of aortic calcifications. The bone minerai density (BMD) results showed a peak value occurring in the 30–35 year old age range (mean 1.1 g cm-2, standard deviation 0.1). The data were compared with a group of 165 normal British women (BW) with a similar age distribution whose peak BMD (obtained with dual X-ray absorptiometry) occurred in the 40–45 year old age range. The two groups were compared in each 10 year age range and the BMD of the OW group was found to be significantly lower in the 40–49 year old age range (P < 0.01) as well as the 50–59 and 60–69 year old age ranges (P < 0.001).