diff --git a/wp-admin/includes/post.php b/wp-admin/includes/post.php
index d9ca48d94f..977b1433e5 100644
--- a/wp-admin/includes/post.php
+++ b/wp-admin/includes/post.php
@@ -499,9 +499,9 @@ function add_meta( $post_ID ) {
 
 	$protected = array( '_wp_attached_file', '_wp_attachment_metadata', '_wp_old_slug', '_wp_page_template' );
 
-	$metakeyselect = stripslashes( trim( $_POST['metakeyselect'] ) );
-	$metakeyinput = stripslashes( trim( $_POST['metakeyinput'] ) );
-	$metavalue = maybe_serialize( stripslashes( trim( $_POST['metavalue'] ) ) );
+	$metakeyselect = isset($_POST['metakeyselect']) ? stripslashes( trim( $_POST['metakeyselect'] ) ) : '';
+	$metakeyinput = isset($_POST['metakeyinput']) ? stripslashes( trim( $_POST['metakeyinput'] ) ) : '';
+	$metavalue = isset($_POST['metavalue']) ? maybe_serialize( stripslashes( trim( $_POST['metavalue'] ) ) ) : '';
 
 	if ( ('0' === $metavalue || !empty ( $metavalue ) ) && ((('#NONE#' != $metakeyselect) && !empty ( $metakeyselect) ) || !empty ( $metakeyinput) ) ) {
 		// We have a key/value pair. If both the select and the