Inclusion Criteria:

• Postmenopausal, ambulatory females, "postmenopausal" defined as the absence of menses for at least 12 continuous months)
• In general good health as determined by medical history, physical examination, and laboratory tests
• LS spine BMD T-score between -1.0 and -2.4, inclusive
• At least one analyzable BMD site at both the hip (left or right) and LS spine (at least 3 measurable lumbar spine vertebrae, without fracture or sufficient degenerative disease)
• Currently receiving no medications for the treatment or prevention of osteoporosis
• Had been on continuous HRT for at least 1 year prior to enrollment. The HRT must have ended within 18 months prior to the baseline visit, and the subject must have been off HRT medication for at least 3 months at the time of baseline visit
• Subjects rendered menopausal by surgical procedures between the ages of 55 and 65 years

Exclusion Criteria:

• A history of cancer within 10 years prior to entry into the study, except for relatively "benign" and cured skin cancers such as basal and squamous cell carcinoma
• A history of hyperparathyroidism, hyperthyroidism, osteomalacia, or other metabolic bone disease within one year prior to enrollment
• Any condition or disease that may interfere with the evaluation of at least 3 lumbar vertebrae (not necessarily contiguous), determined in a screening radiograph by a radiologist at the central facility (e.g., confluent aortic calcifications, severe osteoarthritis, spinal fusion, lumbar spine fractures)
• Evidence of clinically significant organic or psychiatric disease on history or physical examination, which in the opinion of the investigator would prevent the patient from completing the study
• Markedly abnormal pretreatment laboratory finds that, in the opinion of the investigator, would prevent the patient from completing the study
• A history of using any of the following medications prior to starting study:
• Any bisphosphonate therapy
• Selective estrogen receptor modulators (SERMs)
• Parathyroid hormone
• Fluorides
• Calcitonin
• Calcitriol (>1.5 mcg/week)
• Corticosteroids on a chronic basis for period equal to or greater then 3 months
• Received a depot injection of >10,000 IU Vitamin D in the past 12 months
• A history of recurrent nephrolithiasis or a history of one episode of nephrolithiasis within 1 year of study entry
• Serum creatinine >1.6 mg/dl
• Unable to sit or stand upright for 30 minutes after taking the morning dose of risedronate
• A history of deep vein thrombosis or other coagulation disorders
• Severe hepatic insufficiency
• A history of hypersensitivity to raloxifene, risedronate, or to drugs with similar chemical structures
• Clinically relevant cardiovascular, hepatic, neurological, endocrine, or other major systemic disease making implementation of the protocol or interpretation of the study results difficult
• Subjects found to have one or more vertebral fractures after completing thoracic and LS spine films
• Subjects who have experienced a low impact fracture related to osteopenia within two years of baseline visit

The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial