diff --git a/reactos/drivers/usb/nt4compat/usbdrv/devmgr.c b/reactos/drivers/usb/nt4compat/usbdrv/devmgr.c
index a1357f26f6d..6b0862aebb2 100644
--- a/reactos/drivers/usb/nt4compat/usbdrv/devmgr.c
+++ b/reactos/drivers/usb/nt4compat/usbdrv/devmgr.c
@@ -1499,6 +1499,7 @@ dev_mgr_remove_irp(PUSB_DEV_MANAGER dev_mgr, PIRP pirp)
 }
 
 VOID
+NTAPI
 dev_mgr_cancel_irp(PDEVICE_OBJECT dev_obj, PIRP pirp)
 {
     PUSB_DEV_MANAGER dev_mgr;
diff --git a/reactos/drivers/usb/nt4compat/usbdrv/devmgr.h b/reactos/drivers/usb/nt4compat/usbdrv/devmgr.h
index 50d3b6fe6d6..f90c9f0974c 100644
--- a/reactos/drivers/usb/nt4compat/usbdrv/devmgr.h
+++ b/reactos/drivers/usb/nt4compat/usbdrv/devmgr.h
@@ -276,6 +276,6 @@ VOID dev_mgr_event_select_driver(PUSB_DEV pdev, ULONG event, ULONG context, ULON
 LONG dev_mgr_score_driver_for_dev(PUSB_DEV_MANAGER dev_mgr, PUSB_DRIVER pdriver, PUSB_DEVICE_DESC pdev_desc);
 NTSTATUS dev_mgr_destroy_usb_config(PUSB_CONFIGURATION pcfg);
 BOOLEAN dev_mgr_start_select_driver(PUSB_DEV pdev);
-VOID dev_mgr_cancel_irp(PDEVICE_OBJECT pdev_obj, PIRP pirp);
+VOID NTAPI dev_mgr_cancel_irp(PDEVICE_OBJECT pdev_obj, PIRP pirp);
 
 #endif