diff --git a/EdkCompatibilityPkg/Foundation/Efi/Include/EfiApi.h b/EdkCompatibilityPkg/Foundation/Efi/Include/EfiApi.h
index 052f45b5de..4aeb83f719 100644
--- a/EdkCompatibilityPkg/Foundation/Efi/Include/EfiApi.h
+++ b/EdkCompatibilityPkg/Foundation/Efi/Include/EfiApi.h
@@ -910,7 +910,7 @@ EFI_STATUS
 //
 // EFI Runtime Services Table
 //
-#define EFI_RUNTIME_SERVICES_SIGNATURE  0x56524553544e5552
+#define EFI_RUNTIME_SERVICES_SIGNATURE  0x56524553544e5552ULL
 #define EFI_RUNTIME_SERVICES_REVISION   EFI_SPECIFICATION_VERSION
 
 typedef struct {
@@ -964,7 +964,7 @@ typedef struct {
 //
 // EFI Boot Services Table
 //
-#define EFI_BOOT_SERVICES_SIGNATURE 0x56524553544f4f42
+#define EFI_BOOT_SERVICES_SIGNATURE 0x56524553544f4f42ULL
 #define EFI_BOOT_SERVICES_REVISION  EFI_SPECIFICATION_VERSION
 
 typedef struct {
@@ -1081,7 +1081,7 @@ typedef struct {
 //
 // EFI System Table
 //
-#define EFI_SYSTEM_TABLE_SIGNATURE      0x5453595320494249
+#define EFI_SYSTEM_TABLE_SIGNATURE      0x5453595320494249ULL
 #define EFI_SYSTEM_TABLE_REVISION       EFI_SPECIFICATION_VERSION
 #define EFI_1_02_SYSTEM_TABLE_REVISION  ((1 << 16) | 02)
 #define EFI_1_10_SYSTEM_TABLE_REVISION  ((1 << 16) | 10)