19 randomized controlled trials were included in this systematic review which investigated the effect bisphosphonates on decreasing fracture risk and increasing bone mineral density in osteoporotic and osteopenic postmenopausal women. 17 studies were used for quantitative synthesis. The two drugs which were evaluated were alendronate and zoledronate. At a minimum of 1 year follow-up, hip and vertebral fracture risk was significantly reduced with both treatments. Alendronate was also associated with significant increases in bone mineral density at the total hip, femoral neck, and lumbar spine, although meta-analysis for BMD could not be performed for zoledronate.