The results of locked intramedullary osteosynthesis in 48 patients with pseudarthrosis and nonunion of the tibia, from 6 months to 4 years, have been observed. In 27 cases the patients had been previously operated by means of external fixation with Ilizarov apparatus, and with plates. We achieved union in 44 patients (91,6%) at 10 - 1,3 months, including 4 from 6 patients with bone defects and osteomyelitis of the tibia with remission. The results of treatment allow the application of locked intramedullary osteosynthesis in complicated pseudarthrosis.