Interlocked intramedullary nailing is an accepted technique in the management of closed femoral shaft fractures. If this technique is used in patients who are skeletally immature, the position of locking screws relative to soft tissues can alter with time. We present a case of an 11-year-old male who developed a delayed pseudoaneurysm 4 years after intramedullary nailing that was most likely produced by movement of the distal locking screws of his femoral nail in relation to the surrounding vascular structures.