Hyperplastic callus formation has been reported in patients with osteogenesis imperfecta following fractures but not following intramedullary rodding. The present case is that of a child who developed massive hyperplastic callus following osteotomy and intramedullary rodding of all lower extremity bones. Noted complications of intramedullary rodding include refracture, delayed union, nonunion, and pin migration, and it is our belief that hyperplastic callus formation should be considered another potential complication.