Osteoporosis is an important feature of osteogenesis imperfecta (OI). So far, no effective medical treatment is available. We treated three boys with severe OI type III and vertebral deformities for 5-7 years with continuous oral administration of the bisphosphonate, olpadronate. Treatment resulted in a decreased number of bone fractures, an increased calcification of the long bones and an amelioration of vertebral shape. No side-effects were encountered. CONCLUSION: These preliminary but long-term observations suggest that the bisphosphonate olpadronate may be a useful treatment for patients with OI and vertebral fractures. Bisphosphonates may be promising drugs for children with OI.