A consecutive series of 23 aseptic pseudarthroses of the tibial shaft is proposed. The aetiology of a pseudarthrosis of the tibia depends on the original fracture form, the associated soft tissue injury, the treatment technique and the surgical procedure. Twelve times the pseudarthrosis developed after a primary treatment with an external fixation device, 6 times after plaster cast immobilization, and 5 times after plate osteosynthesis. Fifteen times, the pseudarthrosis was hypertrophic, and 8 times hypotrophic. Sixteen pseudarthroses were treated with a plate osteosynthesis, 8 times in combination with a decortication and a cancellous bone grafting. Seven times, a closed intramedullary nailing was performed. Healing was achieved after an average time of 5.1 month. After plaster cast immobilization and external fixation treatment, the non-union is caused by a lack of stability in the fracture region; after plate osteosynthesis by a too extensive decortication, resulting in fragment necrosis. Stability and vitality in the fracture site are the principles in the treatment of the pseudarthrosis.