diff --git a/lib/nghttp2_frame.c b/lib/nghttp2_frame.c
index 1595c49a..1c0e9bcc 100644
--- a/lib/nghttp2_frame.c
+++ b/lib/nghttp2_frame.c
@@ -91,8 +91,8 @@ void nghttp2_frame_headers_free(nghttp2_headers *frame)
 void nghttp2_frame_priority_init(nghttp2_priority *frame, int32_t stream_id,
                                  const nghttp2_priority_spec *pri_spec)
 {
-  frame_set_hd(&frame->hd, 5, NGHTTP2_PRIORITY, NGHTTP2_FLAG_NONE,
-               stream_id);
+  frame_set_hd(&frame->hd, NGHTTP2_PRIORITY_SPECLEN, NGHTTP2_PRIORITY,
+               NGHTTP2_FLAG_NONE, stream_id);
   frame->pri_spec = *pri_spec;
 }
 
@@ -262,7 +262,7 @@ void nghttp2_frame_private_data_free(nghttp2_private_data *frame)
 size_t nghttp2_frame_priority_len(uint8_t flags)
 {
   if(flags & NGHTTP2_FLAG_PRIORITY) {
-    return 5;
+    return NGHTTP2_PRIORITY_SPECLEN;
   }
 
   return 0;
@@ -436,7 +436,7 @@ int nghttp2_frame_pack_priority(nghttp2_bufs *bufs, nghttp2_priority *frame)
 
   buf = &bufs->head->buf;
 
-  assert(nghttp2_buf_avail(buf) >= 5);
+  assert(nghttp2_buf_avail(buf) >= NGHTTP2_PRIORITY_SPECLEN);
 
   buf->pos -= NGHTTP2_FRAME_HDLEN;
 
@@ -444,7 +444,7 @@ int nghttp2_frame_pack_priority(nghttp2_bufs *bufs, nghttp2_priority *frame)
 
   nghttp2_frame_pack_priority_spec(buf->last, &frame->pri_spec);
 
-  buf->last += 5;
+  buf->last += NGHTTP2_PRIORITY_SPECLEN;
 
   return 0;
 }
diff --git a/lib/nghttp2_frame.h b/lib/nghttp2_frame.h
index a9f9abb2..cf8e667a 100644
--- a/lib/nghttp2_frame.h
+++ b/lib/nghttp2_frame.h
@@ -60,6 +60,8 @@
 /* The maximum header table size in SETTINGS_HEADER_TABLE_SIZE */
 #define NGHTTP2_MAX_HEADER_TABLE_SIZE ((1u << 31) - 1)
 
+/* Length of priority related fields in HEADERS/PRIORITY frames */
+#define NGHTTP2_PRIORITY_SPECLEN 5
 
 /* Length of fixed part in ALTSVC frame, that is the sum of fields of
    Max-Age, Port, Reserved and PID_LEN. */
diff --git a/lib/nghttp2_session.c b/lib/nghttp2_session.c
index 6c309dbf..91356d2e 100644
--- a/lib/nghttp2_session.c
+++ b/lib/nghttp2_session.c
@@ -4342,7 +4342,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session,
 
         iframe->frame.hd.flags = NGHTTP2_FLAG_NONE;
 
-        if(iframe->payloadleft != 5) {
+        if(iframe->payloadleft != NGHTTP2_PRIORITY_SPECLEN) {
           busy = 1;
 
           iframe->state = NGHTTP2_IB_FRAME_SIZE_ERROR;
@@ -4352,7 +4352,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session,
 
         iframe->state = NGHTTP2_IB_READ_NBYTE;
 
-        inbound_frame_set_mark(iframe, 5);
+        inbound_frame_set_mark(iframe, NGHTTP2_PRIORITY_SPECLEN);
 
         break;
       case NGHTTP2_RST_STREAM: