From a multicentric study on Congenital Pseudoarthrosis of the tibia (CPT) conducted on 340 patients, we evaluated the functional results on a group of thirty patients who were at the end of skeletal growth (age < or = 16 years). The prognosis of CPT is very much related to the radiologic classification. Crawford type 2 and Crawford type 4 pseudoarthrosis have a worse prognosis, with a lower percentage of fusion at the site of pseudoarthrosis. Crawford 4 patients have the worst functional results. Most of them showed a severe leg length discrepancy, needed a permanent brace, with an ankle joint function fair or poor. The presence of fibula pseudoarthrosis seems to be responsible for most of the worst functional results. The level of deformity caused by either the natural course of the disease or its treatment, is decisive in the evaluation of the functional results.