This trial will examine the safety, efficacy and feasibility of a single dose of intravenous zoledronic acid in the maintenance of skeletal integrity for frail, institutionalized women, who are most at risk for the deleterious outcomes of osteoporosis. The investigators will test the hypothesis that in institutionalized elderly women a single dose of intravenous zoledronic acid therapy will: (1) be efficacious as demonstrated by stability or improvement in bone mass measurements and reductions in bone turnover; (2) be safe and feasible; and (3) provide estimates for vertebral and nonvertebral fracture reduction in this cohort for use in planning a future study.