diff --git a/MdeModulePkg/Core/Dxe/Mem/Imem.h b/MdeModulePkg/Core/Dxe/Mem/Imem.h
index 2f0bf2bf63..84027d628b 100644
--- a/MdeModulePkg/Core/Dxe/Mem/Imem.h
+++ b/MdeModulePkg/Core/Dxe/Mem/Imem.h
@@ -9,22 +9,6 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 #ifndef _IMEM_H_
 #define _IMEM_H_
 
-//
-// +---------------------------------------------------+
-// | 0..(EfiMaxMemoryType - 1)    - Normal memory type |
-// +---------------------------------------------------+
-// | EfiMaxMemoryType..0x6FFFFFFF - Invalid            |
-// +---------------------------------------------------+
-// | 0x70000000..0x7FFFFFFF       - OEM reserved       |
-// +---------------------------------------------------+
-// | 0x80000000..0xFFFFFFFF       - OS reserved        |
-// +---------------------------------------------------+
-//
-#define MEMORY_TYPE_OS_RESERVED_MIN   0x80000000
-#define MEMORY_TYPE_OS_RESERVED_MAX   0xFFFFFFFF
-#define MEMORY_TYPE_OEM_RESERVED_MIN  0x70000000
-#define MEMORY_TYPE_OEM_RESERVED_MAX  0x7FFFFFFF
-
 //
 // MEMORY_MAP_ENTRY
 //