diff --git a/lib/puppet/parser/functions/ensure_packages.rb b/lib/puppet/parser/functions/ensure_packages.rb
index 439af1e92..6c59b20cf 100644
--- a/lib/puppet/parser/functions/ensure_packages.rb
+++ b/lib/puppet/parser/functions/ensure_packages.rb
@@ -37,7 +37,9 @@ module Puppet::Parser::Functions
 
       Puppet::Parser::Functions.function(:ensure_resource)
       packages.each { |package_name|
+      if !findresource("Package[#{package_name}]")
         function_ensure_resource(['package', package_name, defaults ])
+      end
     }
     end
   end