diff --git a/Headers/gnustep/base/String.h b/Headers/gnustep/base/String.h
index c2bbd1476..5407cdd8e 100644
--- a/Headers/gnustep/base/String.h
+++ b/Headers/gnustep/base/String.h
@@ -47,7 +47,7 @@ typedef unsigned short Character;
 
 /* Think about changing these names to avoid conflicts with OpenStep? */
 
-@protocol String <ValueGetting, NSString>
+@protocol String <ValueGetting, IndexedCollecting, NSString>
 
 // INITIALIZING NEWLY ALLOCATED STRINGS.  DON'T FORGET TO RELEASE THEM!;
 - init;
diff --git a/Source/objects/String.h b/Source/objects/String.h
index c2bbd1476..5407cdd8e 100644
--- a/Source/objects/String.h
+++ b/Source/objects/String.h
@@ -47,7 +47,7 @@ typedef unsigned short Character;
 
 /* Think about changing these names to avoid conflicts with OpenStep? */
 
-@protocol String <ValueGetting, NSString>
+@protocol String <ValueGetting, IndexedCollecting, NSString>
 
 // INITIALIZING NEWLY ALLOCATED STRINGS.  DON'T FORGET TO RELEASE THEM!;
 - init;