The present study was done in the dept. of Anatomy with collaboration of dept.of Orthopedics The aim of study was to compare the effect body mass index on bone mineral density in obese persons. • Obesity is condition of excvssive body fat that causes several public health problems Body mass index is calculated by height and weight Body Mass Index = Weight in Kg/Height in M2 • Obesity and osteoporosis are two common complex diseases with multifactorial etiology. Strong positive association between body mass index and bone mineral density is well defined in postmenopausal women but not in men. (Tooth e et al 2005) • The present study was conducted on 200 subjects of age above 20 years. The weight and height of each subject was measured with the help of weighing machine and body mass index was calculated by above formula Bone mineral density was obtained with ultra sonographic bone ensitometer. The distal end of radius and mid shaft of tibia were the sites used for measuring B.M. D. The present study concluded that there is no co- relation between body mass index and bone mineral density and it is statistically significant.