A case of extensive lower limb lengthening (32 cm) in a 14-year-old male patient with Ollier's disease is reported. A varus deformity of the femur and a valgus deformity of the tibia were evident. The femur was successfully lengthened 22 cm by metaphyseal distraction, and the tibia was lengthened 10 cm by two-stage distraction-compression method with a cylindrical bone allograft. Ilizarov's distraction device was used. Radiologically, a good bone regenerate was formed. Host bone has incorporated (like sarcophagi) the allograft of tibia. No evidence of vascular or neural disturbances was found. The lengthening indices were counted for femur 22.5 days per centimeter and for tibia 21 days per centimeter, altogether 15.5 days per centimeter. Bone lengthening was performed through the Ollier's disease foci. Fine needle biopsy investigation showed that most embryonic cartilage cells had been replaced with bone tissue. After five years and a 25-year follow-up the patient was satisfied with the result. The function of the knee joint was limited, but the limb was fully weight-bearing. Signs of knee osteoarthritis were found.