The objective of this study was to compare efficacy and safety of continuous versus intermittent oral dosing of ibandronate. Two hundred forty women aged 55-75 years with postmenopausal osteoporosis were randomized to active treatment or placebo. Similar total doses of ibandronate were provided by treatment regimens with either continuous 2.5 mg of ibandronate daily (n ‫؍‬ 81) or intermittent 20 mg of ibandronate every other day for the first 24 days, followed by 9 weeks without active drug (n ‫؍‬ 78). The placebo group (total, n ‫؍‬ 81) was crossed over after 12 months to receive either continuous (n ‫؍‬ 37) or intermittent ibandronate (n ‫؍‬ 35). By 24 months, bone mineral density (BMD) had increased significantly relative to baseline in both active treatment groups. The continuous and intermittent groups showed statistically equivalent increases in lumbar spine BMD of ؉5.64% (؎0.53) and ؉5.54%