PURPOSE: We measured the BMD (bone mineral density) of elderly patients with hip fracture in order to understand the relationship between osteoporosis and hip fracture, and also to suggest a reference point for starting an osteoporosis treatment program. MATERIALS AND METHODS: From February 2004 to April 2007, we investigated 172 elderly hip fracture patients. Their BMD was checked by DEXA (Hologic QDR-4500w, S/N 49492) at the proximal femur and at the 1st to 4th lumbar vertebrae. The average T-score of the hip fracture patients and the fracture threshold was calculated. RESULTS: The average BMD of the patients with hip fracture was -2.63 of the T-score in the proximal femur and - 2.95 of that in the lumbar vertebrae. The BMD in the patients with intertrochanteric fracture was significantly decreased compared to that of femur neck fracture (p=0.04, 0.19). For the femur neck fracture patients, the BMD of the displaced group was decreased compared to that of the undisplaced group (p=0.04, 0.01). The fracture threshold was -1.29 of the T-score in lumbar vertebrae, and the fracture threshold was -1.15 in the proximal femur. CONCLUSION: The BMD in elderly patients with hip fracture was significantly decreased compared that of normal people. For the prevention of hip fracture in elderly patients, we propose that the aggressive treatment of osteoporosis should be started for patients with a T-score less than -1.5.