diff --git a/Configurations/50-masm.conf b/Configurations/50-masm.conf
index 587a1e70e8..9cb767cefe 100644
--- a/Configurations/50-masm.conf
+++ b/Configurations/50-masm.conf
@@ -18,5 +18,6 @@ my %targets = (
         uplink_arch      => 'x86_64',
         asm_arch         => 'x86_64',
         perlasm_scheme   => "masm",
+        multilib         => "-x64",
     },
 );