Osteoporosis is characterized by low bone mass and micro architectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture. It has been difficult to attribute bone loss in aging men to either testosterone or estrogen deficiency. 179 apparently healthy South Indian men in the age group of 40-80 yrs were studied. Body Mass Index (BMI), Bone Mineral Density (BMD) and serum testosterone were estimated. The BMD of L1-L4 vertebrae & left hip were measured using Dual Energy X-ray Absorptiometry (DEXAHologic Delphi W, SN 70462, QDR system software version 11.1). Serum total testosterone was estimated by RIA methods for all individuals. There is a gradual decrease in the BMD-HIP / Incidence of osteoporosis with advancing age. But age has no significant correlation with bone mineral density (BMD-spine -r = 0.0098, P=0.8965, left hip r = -0.1304, P = 0.082). Body mass index (BMI) correlated positively with BMD (BMD-spine -r = 0.318, left hip -r = 0.422, P<0.0001). There is no significant association between BMD and serum total testosterone levels (BMD-spine -r = 0.1947, P = 0.351, BMD left hip-r = 0.2317, P = 0.2651). The increasing incidence of Osteoporosis with advancing age poses a major threat to the elderly population and a low Body Mass Index (BMI) has a significant role in the incidence of Osteoporosis. Serum testosterone has no effect on BMD and the cause of osteoporosis in the elderly remains uncertain.