4.1 Inclusion Criteria 4.1.1 Women not more than 80 years old on date of randomization 4.1.2 At least 1 year postmenopausal on date of randomization 4.1.3 Ambulatory 4.1.4 If ≤ 60 years old or post bilateral oophorectomy based on medical history, will require serum FSH > 50mU/mL or serum estradiol < 20 pg/mL to be eligible; 4.1.5 Low bone mineral density (BMD t-score ≤ -1.8 at any one of the following sites: lumbar spine, femoral neck, or total hip; BMD t-scores must not be lower than -4.0 at the lumbar spine, or -3.5 at the femoral neck or total hip). Refer to Table 3 in Section 7.11.1 for Hologic and Lunar densitometer-specific BMD values, and more specific information. 4.1.6 Ethical - Before any study specific procedure, including the screening DXA, the subject must give informed consent for participation in the study (see Section 12.2). 4.2 Exclusion Criteria 4.2.1 Fluoride treatment for osteoporosis within the last 2 years before the enrollment date; 4.2.2 Bisphosphonate use within the last 12 months before the enrollment date; 4.2.3 Administration of the following medications within the last 6 months before enrollment date:

1. Tibolone
2. Parathyroid hormone (or any derivative)
3. Systemic glucocorticosteroids (> 5 mg oral prednisone equivalent per day for more than 10 days)
4. Inhaled corticosteroids (> 2,000 µg per day for more than 10 days)
5. Anabolic steroids or testosterone 4.2.4 Administration of the following medications within the last 3 months before the enrollment date:

a) Systemic hormone replacement therapy b) Selective estrogen receptor modulators (SERMs) c) Calcitonin d) Calcitriol 4.2.5 Evidence of any of the following conditions per subject self report or medical chart review:

1. Current hyper- or hypothyroidism (stable on thyroid replacement therapy is allowed, if the TSH is within the normal range)
2. Current hyper- or hypoparathyroidism
3. Albumin-adjusted serum calcium < 8.5 mg/dL
4. Osteomalacia
5. Rheumatoid arthritis
6. Paget's disease
7. Malignancy within the last 5 years prior to enrollment (except cervical carcinoma in situ or basal cell carcinoma)

8. Renal disease (creatinine clearance <= 35 mL/min using the following equation):

   Creatinine Clearance = 0.85 [(140 - age in years) x (weight in kg)] [72 x serum creatinine (mg/dL)]

9. Any bone disease, other than osteoporosis, which may interfere with the interpretation of the findings (e.g., osteogenesis imperfecta or osteopetrosis)
10. Malabsorption syndrome
11. Weight, height or girth which may preclude accurate DXA measurements
12. Less than 2 lumbar vertebrae (L1-L4) evaluable by DXA
13. Recent long bone fracture (within 6 months)
14. Osteoporosis-related fracture (i.e., crush or wedge vertebral fracture or hip fracture) known or suspected to have occurred within 2 years of randomization.
15. More than one single, grade 1 vertebral fracture. 4.2.6 Currently enrolled or has participated within the previous 30 days in other investigational device or drug trial(s). For some trials, this may be allowed after discussion and written approval from Amgen. 4.2.7 Known sensitivity to mammalian-derived drug preparations (e.g., Herceptin).

4.2.8 Any organic or psychiatric disorder, serum chemistry, or hematology, which, in the opinion of the investigator, may prevent the subject from completing the study or interfere with the interpretation of the study results. 4.2.9 Self-reported alcohol or drug abuse within the previous 12 months. 4.2.10 Any disorder that compromises ability to give truly informed consent for participation in this study. 4.2.11 Prior administration of AMG 162. 4.2.12 Known sensitivity or contraindication to Fosamax. 4.2.13 Known sensitivity or contraindication to tetracycline derivatives (biopsy subset subjects only).