Male osteoporosis is a common and important clinical problem, associated with significant morbidity, mortality and societal expense. Approximately 10% of men =65 years of age are osteoporotic. The proposed study will evaluate efficacy and safety of oral ibandronate given 150 mg once-monthly for 12 months versus placebo in men with primary osteoporosis. Less frequent, once monthly, dosing is expected to improve patient's treatment adherence compared to a weekly dosing regimen.