diff --git a/lib/nghttp2_hd.h b/lib/nghttp2_hd.h
index cd011a6c..72260ffc 100644
--- a/lib/nghttp2_hd.h
+++ b/lib/nghttp2_hd.h
@@ -38,10 +38,6 @@
 #define NGHTTP2_HD_MAX_ENTRY_SIZE 3072
 #define NGHTTP2_HD_ENTRY_OVERHEAD 32
 
-/* This value is sensible to NGHTTP2_HD_MAX_BUFFER_SIZE. Currently,
-   the index is at most 128, so 255 is good choice */
-#define NGHTTP2_HD_INVALID_INDEX 255
-
 typedef enum {
   NGHTTP2_HD_SIDE_CLIENT = 0,
   NGHTTP2_HD_SIDE_SERVER = 1