Osteogenesis imperfecta is a genetic disorder that causes increased bone fragility and low bone mass. Osteogenesis imperfecta is a rare disease: its estimated prevalence is between 1/10000 and 1/20000 persons. The severity of skeletal and extraskeletal manifestations varies widely. Most patients have a mutation in one of the 2 genes that encode the alpha chains of collagen type I. Treatment with bisphosphonates has produced clear improvements, especially for growing children. The appropriate regimen for bisphosphonate treatment remains to be determined: the goal is to find the lowest effective dose to minimize side effects. Treatment of osteogenesis imperfecta must be multidisciplinary, including physicians, surgeons, and physical therapists.