diff --git a/SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/Ia32/ArchRegisters.h b/SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/Ia32/ArchRegisters.h
index 3c279589e7..909ddbe535 100644
--- a/SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/Ia32/ArchRegisters.h
+++ b/SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/Ia32/ArchRegisters.h
@@ -1,7 +1,7 @@
 /** @file
   IA32 register defintions needed by debug transfer protocol.
 
-  Copyright (c) 2010, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2010 - 2011, Intel Corporation. All rights reserved.<BR>
   This program and the accompanying materials
   are licensed and made available under the terms and conditions of the BSD License
   which accompanies this distribution.  The full text of the license may be found at
@@ -15,6 +15,8 @@
 #ifndef _ARCH_REGISTERS_H_
 #define _ARCH_REGISTERS_H_
 
+#pragma pack(1)
+
 ///
 /// FXSAVE_STATE
 /// FP / MMX / XMM registers (see fxrstor instruction definition)
@@ -153,4 +155,6 @@ typedef struct {
   UINT32         TssBas;
 } DEBUG_DATA_REPONSE_READ_REGISTER_GROUP_SEGBASE_IA32;
 
+#pragma pack()
+
 #endif
diff --git a/SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/X64/ArchRegisters.h b/SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/X64/ArchRegisters.h
index e7a5a33089..9675391956 100644
--- a/SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/X64/ArchRegisters.h
+++ b/SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/X64/ArchRegisters.h
@@ -1,7 +1,7 @@
 /** @file
   X64 register defintions needed by debug transfer protocol.
 
-  Copyright (c) 2010, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2010 - 2011, Intel Corporation. All rights reserved.<BR>
   This program and the accompanying materials
   are licensed and made available under the terms and conditions of the BSD License
   which accompanies this distribution.  The full text of the license may be found at
@@ -15,6 +15,8 @@
 #ifndef _ARCH_REGISTERS_H_
 #define _ARCH_REGISTERS_H_
 
+#pragma pack(1)
+
 ///
 /// FXSAVE_STATE (promoted operation)
 /// FP / MMX / XMM registers (see fxrstor instruction definition)
@@ -325,5 +327,6 @@ typedef struct {
   UINT64         Tssas;
 } DEBUG_DATA_REPONSE_READ_REGISTER_GROUP_SEGMENT_BASES_X64;
 
+#pragma pack()
 
 #endif