We report results of 2-5 y treatment with intravenous disodium pamidronate (APD) in three girls with severe osteogenesis imperfecta (OI). Treatment was given as monthly infusions. Additional oral 1,25-dihydroxy-cholecalciferol was given to compensate for a transient decrease in serum calcium levels. During treatment, DEXA measurements showed a gradual increase in bone density in all patients. All parameters analysed in serum (ALP, osteocalcin, PICP, ICTP) and in urine (deoxypyridinoline and pyridinoline) showed a decreased bone turnover. The two younger patients reported a major improvement in well-being, pain and activities of daily life. The effect on the older patient was less pronounced. No negative side effects in clinical or laboratory variables were observed. This study indicates that APD is of value in the symptomatic treatment of children with severe OI.