diff --git a/Makefile.PL b/Makefile.PL
index 8a01b1d..332f7da 100644
--- a/Makefile.PL
+++ b/Makefile.PL
@@ -10,6 +10,7 @@ WriteMakefile(
   NAME => $package_name,
   VERSION_FROM => 'Filter.pm',
   AUTHOR => 'PerlDL Developers <pdl-general@lists.sourceforge.net>',
+  LICENSE => 'perl',
   CONFIGURE_REQUIRES => {
     'ExtUtils::MakeMaker' => 0,
     'PDL' => '2.096',