"Popcorn" calcifications appear roentgenographically as a collection of scalloped radiolucencies, each with a sclerotic margin and in some instances, with central densities. The radiographs of 46 children with osteogenesis imperfecta were reviewed retrospectively; 52% had "popcorn" calcifications at one or more sites. A study of these children indicated that these lesions are observed only during active skeletal growth, are not present at birth, occur predominantly around the knees and ankles, and are associated with irregularity or absence of the normal horizontal growth plate. Based on multiple roentgen observations, "popcorn" calcifications appear to result from fragmentation and disordered maturation of the physis, and their presence indicates a disturbance in enchondral ossification which may contribute to the severe growth retardation associated with osteogenesis imperfecta.