Using the pretransplant bone mineral density (BMD) data records of renal recipients, we retrospectively examined risk factors affecting posttransplant changes in BMD and the effect of antiosteoporosis management. For 294 kidney transplant recipients from January 1996 to September 2003, BMD values were expressed as spine and femur T-scores. Gender, age, pretransplant diabetes, blood type compatibility, mode and duration of dialysis, and previous transplantation were considered to be variables affecting BMD changes. T-test or ANOVA was used to compare risk factors. At the time of transplantation, mean spine T-scores were significantly lower among the retransplant group. Mean femur T-scores were significantly lower among the retransplant group, older patients (older than 45 years), and female recipients. Prolonged hemodialysis (>12 months) and retransplant were risk factors for BMD loss during the first year posttransplant. Early application of antiosteoporosis management was effective to ameliorate posttransplant BMD loss. However, antiosteoporosis management after 1 year posttransplant was relatively ineffective. Pretransplant evaluation of BMD and the possibility of significant BMD loss during the first posttransplant year should not be overlooked. Prophylaxis against bone loss and treatment should be started as soon as possible after transplantation for recipients with either normal or abnormal pretransplant BMD.