diff --git a/accessible/src/atk/nsRoleMap.h b/accessible/src/atk/nsRoleMap.h
index 93a8e97ceb66..eaad8b4faa8b 100644
--- a/accessible/src/atk/nsRoleMap.h
+++ b/accessible/src/atk/nsRoleMap.h
@@ -41,7 +41,7 @@
 #include <atk/atk.h>
 #include "nsAccessibleWrap.h"
 
-#define ROLE_ATK_LAST_ENTRY -1
+const PRUint32 ROLE_ATK_LAST_ENTRY = 0xffffffff;
 
 // Map array from cross platform roles to  ATK roles
 PRUint32 atkRoleMap[] = {
diff --git a/accessible/src/msaa/nsRoleMap.h b/accessible/src/msaa/nsRoleMap.h
index 3d2718fef1d2..b3dd416652dc 100644
--- a/accessible/src/msaa/nsRoleMap.h
+++ b/accessible/src/msaa/nsRoleMap.h
@@ -40,19 +40,19 @@
 
 #include "OLEACC.H"
 
-#define USE_ROLE_STRING 0
-#define ROLE_MSAA_LAST_ENTRY -1
+const PRUint32 USE_ROLE_STRING = 0;
+const PRUint32 ROLE_MSAA_LAST_ENTRY = 0xffffffff;
 
 #ifndef ROLE_SYSTEM_SPLITBUTTON
-#define ROLE_SYSTEM_SPLITBUTTON ( 0x3e )    // Not defined in all oleacc.h versions
+const PRUint32 ROLE_SYSTEM_SPLITBUTTON  = 0x3e; // Not defined in all oleacc.h versions
 #endif
 
 #ifndef ROLE_SYSTEM_IPADDRESS
-#define ROLE_SYSTEM_IPADDRESS ( 0x3f )      // Not defined in all oleacc.h versions
+const PRUint32 ROLE_SYSTEM_IPADDRESS = 0x3f; // Not defined in all oleacc.h versions
 #endif
 
 #ifndef ROLE_SYSTEM_OUTLINEBUTTON
-#define ROLE_SYSTEM_OUTLINEBUTTON ( 0x40 )  // Not defined in all oleacc.h versions
+const PRUint32 ROLE_SYSTEM_OUTLINEBUTTON = 0x40; // Not defined in all oleacc.h versions
 #endif
 
 // Map array from cross platform roles to MSAA roles