Osteoporosis is a complication of kidney transplantation (KTx). We measured bone mineral density (BMD) before and after KTx to determine the frequency and severity of preoperative and postoperative osteoporosis. We conducted a crass-sectional study of BMD in before (n=40, men: 22 and women: 18) and after (n=61, men: 43 and women: 18) KTx. The prevalence of osteoporosis in lumbar spine and fem neck were more frequent in transplantation group than healthy population of our country (24% vs 4.7%; P<0.001, odds ratio=6.1), (11% vs 2.4%; P=0.01, odds ratio= 6.05) respectively but not significantly different from dialysis group (24% vs 18%, P=0.25), (11% vs 17.5%, P=0.16) respectively. In transplantation group, there were significant negative correlation between BMD of lumbar spine (g/cm2) and cumulative prednisolone dose (r=-0.34, P=0.007), and months since transplantation (r=-0.31, P=0.016). There weren’t any correlation between BMD of lumbar and fem neck and BMI, age and cumulative cyclosporine. The patients in translation group treated by supplement of Ca and vitamin D had less osteoporosis frequency in lumbar spine than patients without treatment (13.8% vs 37.5%, P=0.046). Osteoporosis is more frequent in transplant and dialysis patients than general population. However, there isn’t any difference osteoporosis frequency between transplant and dialysis patients. In lumbar spine, supplement of Ca and vitamin D can prevent osteoporosis and more cumulative prednisolone dose results in decreasing of lumbar BMD in renal transplantation.