diff --git a/template.php b/template.php
index ba6ccd7..533c8e3 100644
--- a/template.php
+++ b/template.php
@@ -373,6 +373,7 @@ function zen_preprocess_region(&$variables, $hook) {
  *   The name of the template being rendered ("block" in this case.)
  */
 function zen_preprocess_block(&$variables, $hook) {
+
   // Use a bare template for the page's main content.
   if ($variables['block_html_id'] == 'block-system-main') {
     $variables['theme_hook_suggestions'][] = 'block__bare';
@@ -389,6 +390,98 @@ function zen_preprocess_block(&$variables, $hook) {
   $variables['classes_array'][] = $variables['block_zebra'];
 
   $variables['title_attributes_array']['class'][] = 'block-title';
+
+  // Add Aria Roles via attributes
+  if ($variables['block']->module == 'aggregator') {
+    $variables['attributes_array']['role'] = 'complementary';
+  }
+  if ($variables['block']->module == 'blog') {
+    $variables['attributes_array']['role'] = 'navigation';
+  }
+  if ($variables['block']->module == 'book') {
+    $variables['attributes_array']['role'] = 'navigation';
+  }
+  if ($variables['block']->module == 'comment') {
+    $variables['attributes_array']['role'] = 'navigation';
+  }
+  if ($variables['block']->module == 'forum') {
+    $variables['attributes_array']['role'] = 'navigation';
+  }
+  if ($variables['block']->module == 'help') {
+    $variables['attributes_array']['role'] = 'complementary';
+  }
+  if ($variables['block']->module == 'locale') {
+    $variables['attributes_array']['role'] = 'complementary';
+  }
+  if ($variables['block']->module == 'menu') {
+    $variables['attributes_array']['role'] = 'navigation';
+  }
+  if ($variables['block']->module == 'poll') {
+    $variables['attributes_array']['role'] = 'complementary';
+  }
+  if ($variables['block']->module == 'profile') {
+    $variables['attributes_array']['role'] = 'complementary';
+  }
+  if ($variables['block']->module == 'search') {
+    $variables['attributes_array']['role'] = 'search';
+  }
+  if ($variables['block']->module == 'shortcut') {
+    $variables['attributes_array']['role'] = 'navigation';
+  }
+  if ($variables['block']->module == 'statistics') {
+    $variables['attributes_array']['role'] = 'navigation';
+  }
+  // System module blocks
+  if ($variables['block']->module == 'system') {
+    switch ($variables['block']->delta) {
+      case 'main':
+        $variables['attributes_array']['role'] = 'main';
+        break;
+
+      case 'powered-by':
+        $variables['attributes_array']['role'] = 'complementary';
+        break;
+
+      case 'help':
+        $variables['attributes_array']['role'] = 'complementary';
+        break;
+
+      // System menu blocks should get the same class as menu module blocks.
+      default:
+      if (in_array($variables['block']->delta, array_keys(menu_list_system_menus()))) {
+        $variables['attributes_array']['role'] = 'navigation';
+        $variables['classes_array'][] = 'block-menu';
+      }
+    }
+  }
+  // User module blocks
+  if ($variables['block']->module == 'user') {
+    switch ($variables['block']->delta) {
+      case 'login':
+        $variables['attributes_array']['role'] = 'form';
+        break;
+
+      case 'new':
+        $variables['attributes_array']['role'] = 'complementary';
+        break;
+
+      case 'online':
+        $variables['attributes_array']['role'] = 'complementary';
+        break;
+    }
+  }
+  // Node module blocks
+  if ($variables['block']->module == 'node') {
+    switch ($variables['block']->delta) {
+      case 'syndicate':
+        $variables['attributes_array']['role'] = 'complementary';
+        break;
+
+      case 'recent':
+        $variables['attributes_array']['role'] = 'navigation';
+        break;
+    }
+  }
 }
 
 /**