Clinical experience with 99mTc-methylenediphosphonate was presented in 115 patients with trauma, who were treated at Seoul University Hospital from Jan. 1980 to Dec. 1983. The results were summarized as followings: 1. Bone scan exhibited increased uptake in all cases examined within 1 year of trauma and the frequency of scan positivity was diminished as the interval between trauma and the scan increased. 2. The possible factors associated with positive scans in cases more than 2 years after trauma were malunion and post-traumatic arthritis, but the age, general condition of the patient were not appeared to be significantly related to persistent positive scan. 3. Bone scan was thought to be sensitive enough to detect early stress fracture ot accompanied by radiographic abnormali ty. 4. It seemed to be reasonable to judge that the fracture was old when the bone scan of vertebral compression fracture in the young age group was negative except very early stage of trauina. 5. Bone scan was very sensitive to find early post-traumatic avascuhr necrosis in femoral neck fracture when the roentgenographic finding was equivocal.