The Williams Y-nail is a modified interlocking Kiintscher Y-nail that is indicated for a wide variety of difficult proximal femoral fractures. In contrast to the classical Kiintscher Y-nailing procedure, the Williams Y-nailing technique requires intramedullary reaming and proximal set-screw locking. Distal interlocking is available and allows this device, unlike the original Kiintscher Y-nail, to be used in the management of type III and IV comminuted fractures. Although the technique is demanding, the clinical results have been favorable in patients with unstable subtrochanteric-intertrochanteric and ipsilateral trochanteric-diaphyseal fractures. The Williams Y-nail works well in complex proximal trochanteric fractures; however, because it has been associated with an increased risk of failure when used in the management of femoral neck fractures, its use for combined neck-shaft fractures is uncertain.