Closed intramedullary nailing is a complex technique which usually requires fracture table and image intensifier, so that the patient and surgeon are exposed to the radiation. But this technique affords considerable advantages such as high rate of union, less infection rate and early weight bearing, etc. The main causes of failure or complication of this procedure are inapproprisate entry point and inadequate nail size. These are especially important problems in the patient who is femoral canal diameter is very small (8 or 9mm). The Delta femoral interlocking nails (diameter 10mm and 11mm)were devised for the femurs with narrow canal diameter. However, proximal portion of the Delta nail (about 7cm from the proximal end)is thick (diameter 13mm)to gain strength enough for holding the insertion device and fixation of the interlocking screws. If the insertion point is not correct or proximal reaming is inadequate, iatrogenic proximal femoral fracture may occur during final insertion of the nail. We experienced 2 cases of this complication during fixation of femoral shaft fractures using the Delta nails. We managed thls problem with hip spica cast immobilization in one case, and multiple pinning of femur neck in the other.