The authors reviewed 51 patients with a fracture of the tibia primarily treated with an unreamed intramedullary nail. There were 29 open and 22 closed fractures. All fractures healed within one year of the trauma. There were no deep infections. The most frequently observed complication was failure of interlocking screws (20%), but this complication had a negligible influence on bone healing. Re-nailing with a reamed nail was necessary in 18%. According to the criteria of Klemm and Börner an excellent result was obtained in 55% and a good result in 44%. The authors recommend unreamed nailing in fractures with soft tissue injuries; they recommend to dynamize the implant after six weeks in transverse and short oblique fractures and to replace the unreamed nail by a reamed one after three months in case of delayed union.