PHP include within templates?

[HappyPike]

Is it possible to use PHP include inside the templates to include a file?

For example, my layout has something like

PHP Code:

<?php
include_once("../includes/header.php");
?>
some content
<?php
include_once("../includes/footer.php");
?>

I tried putting this directly inside the template but it doesn't get parsed. Thanks in advanced for any help.