This study was designed to determine the ability of quantitative ultrasound (QUS) of the heel to predict fracture risk at different sites in postmenopausal women between the ages of 45 and 75 years. Heel QUS was measured at baseline using a Lunar Achilles scanner, and subsequent fractures were identified over 3 yr. The results were analyzed graphically after age adjustment and using Cox's proportional regression to estimate odds ratios for fracture risk; 3180 women were scanned (79% of sample). Sixty-three wrist, 12 hip, 4 vertebral, 7 proximal humerus, 3 pelvic, and 61 other fractures were identified over a mean followup of 31 mo. There was a fivefold difference in numbers of wrist and osteoporosis-related fractures (hip, vertebra, pelvis, and humerus combined) between the lowest and highest quartiles of QUS results adjusted for age. The odds ratios per 1 SD decline in QUS parameters adjusted for age were: wrist fractures BUA = 1.6, SOS = 1.5, stiffness = 1.8, osteoporosis-related fractures BUA = 1.9, speed of sound (SOS) = 1.6, stiffness = 2.2, and other fractures, BUA = 1.0, SOS = 1.1, stiffness = 1.1. When analyzed for each 10-yr age group, the odds ratios were generally higher in the 56-65 yr group than the other decades. In women between 45 and 75 yr, heel QUS can predict wrist and osteoporosis-related fractures at about the same level that dual-energy X-ray absorptiometry (DXA) of various sites can predict wrist fractures. This extends the current evidence that heel QUS can predict hip fracture risk in women over 75 yr to include other fracture sites in younger women. Heel QUS may be useful in the primary care assessment of osteoporotic fracture risk in women after the menopause.