From 21 non osteogenic fibromas submited to surgery, authors bring their surgical experience of that tumor. This frequent benign tumor of the bone in childwood has generally a good pronostic; it evolves to spontaneous recovery in most of the cases. It is often latent, asymptomatic, and of an accidental diagnosis. The roentgenographic exam allows most often an accurate diagnosis. Sometimes it remains doubtful, and a biopsy is then necessary. The histologic exam will easily confirm the nature of the lesion. In half of the cases, non ossifying fibroma is revealed by a spontaneous fracture. It seems illusive to hope a complete filling of the tumor cavity with an orthopaedic treatment alone; it must be done a resection of the tumor together with a bone graft and an osteosynthesis. In the end, in some cases of a fortuitous diagnosis, the bone is made so weak that a resection with bone graft is necessary. And so, during the evolution of non osteogenic fibroma, there is a certain place for surgical treatment.