Seventeen femoral nonunions after intramedullary nail internal fixation were treated with augmentative plate internal fixation. Six of them were initially managed with a Küntscher nail internal fixation; the other 11 fractures were managed with a locked nail internal fixation. All the femoral nonunions were caused by insecure fixation of the intramedullary nailing, in which a rotational instability of the fracture site was verified in all cases during operation. Leaving the intramedullary nail in situ, an augmentative plate fixation was applied to the fracture site to counter the rotational instability. A simultaneous bone grafting was performed in seven of them to repair the bony defect. All these patients walked bearing full weight on the extremity without aching at the fracture site within 3 months and all these 17 fractures obtained a bony union within an average of 7 months after this treatment. From our experience, we have found this method is a useful treatment for the nonunion of the femoral shaft fracture after an intramedullary nail internal fixation. The technique is simple and does not require any special instrument. It facilitates an early weight bearing and gives a quick recovery from nonunion.