diff --git a/base/modules/psb_base_mod.f90 b/base/modules/psb_base_mod.f90
index c042135b..71a95bb7 100644
--- a/base/modules/psb_base_mod.f90
+++ b/base/modules/psb_base_mod.f90
@@ -34,6 +34,7 @@ module psb_base_mod
   use psb_error_mod
   use psb_penv_mod
   use psb_check_mod
+  use psb_sort_mod
   use psb_desc_mod
   use psb_linmap_mod
   use psb_vect_mod