PURPOSE: To evaluate the effectiveness of bone scintigraphy using 99mTc-methylene diphosphonate(99mTc-MDP) for prediction of viability of femoral head in femur neck fracture that have been treated with osteosynthesis. MATERIALS AND METHOD: Thirty two patients were included in this study who underwent preoperative and postoperative bone scintigraphy using 99mTc-MDP following femur neck fracture. The uptake of istope was estimated visually as either normal or reduced compared with the opposite side. The complications as avascular necrosis and non-union were checked and compared with the preoperative and postoperative bone scintigraphy and the predictive values of positive and negative scintigraphy were calculated. RESULTS: Among thirty-two patients, bone union occured in nineteen patients except 12 avascular necrosis and 1 non-union. Average bone union peried was 4.4 months and 50% was occured between 3 and 6 months. In seventeen patients who showed reduced isotope uptake, twelve patients developed complications and predictive value of positive scintigraphy was calculated as 0.76. In fifteen patients shown normal isotope uptake, none developed complications and predictive value of negative scintigraphy was calculated as 1.00. CONCLUSION: Preoperative bone scintigraphy using 99mTc-MDP was useful method to evaluate the viability of femoral head following femur neck fracture and to choose the treatment modality of displaced femur neck fracture especially in elderly person.