In a series of 32 patients, the tibia was lengthened nine times and the femur 26 times. The lengthening was 4.1 cm in the tibia and 4.9 cm in the femur. The callotasis principle and atraumatic handling of the periosteum were considered important. The leg inequality was corrected appropriately, except in cases where the leglength inequality was > 12 cm as a result of a progressive congenital deformity. Late femoral fractures occurred in six patients, but no tibial fractures were seen. One hip dislocation was seen after femoral lengthening, one talus deformation developed after the tibial lengthening, and one peroneal nerve entrapment was released operatively. One infection caused delayed bone union. Average follow-up time was 5.0 years.