diff --git a/include/ddk/hidsdi.h b/include/ddk/hidsdi.h
index 566d0301ac1..c8a0d735e0a 100644
--- a/include/ddk/hidsdi.h
+++ b/include/ddk/hidsdi.h
@@ -39,6 +39,7 @@ void WINAPI HidD_GetHidGuid(LPGUID guid);
 BOOLEAN WINAPI HidD_GetInputReport(HANDLE HidDeviceObject, PVOID ReportBuffer, ULONG ReportBufferLength);
 BOOLEAN WINAPI HidD_GetManufacturerString(HANDLE HidDeviceObject, PVOID Buffer, ULONG BufferLength);
 BOOLEAN WINAPI HidD_GetProductString(HANDLE HidDeviceObject, PVOID Buffer, ULONG BufferLength);
+BOOLEAN WINAPI HidD_GetSerialNumberString(HANDLE HidDeviceObject, PVOID Buffer, ULONG BufferLength);
 BOOLEAN WINAPI HidD_SetFeature(HANDLE HidDeviceObject, PVOID ReportBuffer, ULONG ReportBufferLength);
 BOOLEAN WINAPI HidD_GetPreparsedData( HANDLE HidDeviceObject, PHIDP_PREPARSED_DATA *PreparsedData);
 BOOLEAN WINAPI HidD_FreePreparsedData(PHIDP_PREPARSED_DATA PreparsedData);