diff --git a/reactos/drivers/input/kbdclass/kbdclass.c b/reactos/drivers/input/kbdclass/kbdclass.c
index 8441d9a4818..8ca7208c0b4 100644
--- a/reactos/drivers/input/kbdclass/kbdclass.c
+++ b/reactos/drivers/input/kbdclass/kbdclass.c
@@ -438,7 +438,7 @@ FillEntries(
 	return Status;
 }
 
-static BOOLEAN
+static BOOLEAN CALLBACK
 ClassCallback(
 	IN PDEVICE_OBJECT ClassDeviceObject,
 	IN OUT PKEYBOARD_INPUT_DATA DataStart,
diff --git a/reactos/drivers/input/mouclass/mouclass.c b/reactos/drivers/input/mouclass/mouclass.c
index 46a3feeb674..ec2aec5a238 100644
--- a/reactos/drivers/input/mouclass/mouclass.c
+++ b/reactos/drivers/input/mouclass/mouclass.c
@@ -414,7 +414,7 @@ FillEntries(
 	return Status;
 }
 
-static BOOLEAN
+static BOOLEAN CALLBACK
 ClassCallback(
 	IN PDEVICE_OBJECT ClassDeviceObject,
 	IN OUT PMOUSE_INPUT_DATA DataStart,