diff --git a/libguile/strings.c b/libguile/strings.c
index bf7266e4e..87ced8f21 100644
--- a/libguile/strings.c
+++ b/libguile/strings.c
@@ -407,8 +407,8 @@ scm_i_c_make_symbol (const char *name, size_t len,
   SCM buf = make_stringbuf (len);
   memcpy (STRINGBUF_CHARS (buf), name, len);
 
-  return scm_double_cell (scm_tc7_symbol | flags, SCM_UNPACK (buf),
-			  (scm_t_bits) hash, SCM_UNPACK (props));
+  return scm_immutable_double_cell (scm_tc7_symbol | flags, SCM_UNPACK (buf),
+				    (scm_t_bits) hash, SCM_UNPACK (props));
 }
 
 /* Return a new symbol that uses the LEN bytes pointed to by NAME as its