diff --git a/include/cyclone/runtime.h b/include/cyclone/runtime.h
index fef267ca..4645409f 100644
--- a/include/cyclone/runtime.h
+++ b/include/cyclone/runtime.h
@@ -394,7 +394,8 @@ int equal(object, object);
 object equalp(object, object);
 object Cyc_has_cycle(object lst);
 object Cyc_is_boolean(object o);
-object Cyc_is_pair(object o);
+//object Cyc_is_pair(object o);
+#define Cyc_is_pair(o) ((is_object_type(o) && ((list) o)->tag == pair_tag) ? boolean_t : boolean_f)
 object Cyc_is_null(object o);
 object Cyc_is_number(object o);
 object Cyc_is_real(object o);
diff --git a/runtime.c b/runtime.c
index 298ab334..7c544d17 100644
--- a/runtime.c
+++ b/runtime.c
@@ -1474,12 +1474,12 @@ object Cyc_is_boolean(object o)
   return boolean_f;
 }
 
-object Cyc_is_pair(object o)
-{
-  if (is_object_type(o) && ((list) o)->tag == pair_tag)
-    return boolean_t;
-  return boolean_f;
-}
+//object Cyc_is_pair(object o)
+//{
+//  if (is_object_type(o) && ((list) o)->tag == pair_tag)
+//    return boolean_t;
+//  return boolean_f;
+//}
 
 object Cyc_is_null(object o)
 {