Intramedullary reamed locking nail of open fractures remains controversial because of the risk of infection. 1,474 closed reamed locked nailings were performed between 1974 and 1989 for femoral (744 cases) or tibial (730 cases) fractures. 349 fractures were open: 100 femoral fractures (51 Gustilo and Anderson Grade I and 49 Grade II) and 249 tibial fractures (140 Grade I, 99 Grade II et 10 Grade III). 24 femoral (3.2%) and 46 tibial (6.3%) nails were followed by infection. This difference is significant (p < 0.01). Reoperations for infection occur more frequently for femoral than tibial fractures (p < 0.05). There is no difference between the results of infection treatment between femoral or tibial fractures. Traumatic opening of the femoral fracture site does not affect the occurrence of an infection, its severity or the results of its treatment. Traumatic opening of the tibial fracture site significantly increases the infection rate (p < 0.001), and the incidence of infection increases with the severity of the soft tissue lesions; but the severity of the infection and the results of its treatment are not modified. Acute closed reamed intramedullary locking nail is the best treatment for open femoral or tibial fractures with respect to the bone healing and infection rate for Grade I and II fractures. For Grade III fractures, nailing must be followed by a coverage flap.