This would help if you don't want to modify your code much

#!/usr/bin/perl
use warnings;
use strict;

my $List = "/bin/ls";
my $tmp = "/tmp";
my $var = "/var";
my ($Results1, $Results2);
&DoList();

print "Tmp is\n$Results1\n";

print "Var is\n$Results2\n";

sub DoList {
    $Results1 = `$List $tmp`;
    $Results2 = `$List $var`;
}
[download]

But mind this..global variables are discouraged in larger scripts.The safe thing is to assign the return value(s) as suggested by moritz.