diff --git a/commerce_checkout_progress.module b/commerce_checkout_progress.module
index c41aeb0..1e66921 100644
--- a/commerce_checkout_progress.module
+++ b/commerce_checkout_progress.module
@@ -171,10 +171,10 @@ function theme_commerce_checkout_progress_list($variables) {
       // Active page and next pages should not be linked.
       $visited = FALSE;
     }
-    if ($page_id === $items[$current_page]['prev_page']) {
+    if (!empty($items[$current_page]['prev_page']) && $page_id === $items[$current_page]['prev_page']) {
       $class[] = 'previous';
     }
-    if ($page_id === $items[$current_page]['next_page']) {
+    if (!empty($items[$current_page]['next_page']) && $page_id === $items[$current_page]['next_page']) {
       $class[] = 'next';
     }
     // @TODO: Calculate width based on 100 / qty of pages.