diff --git a/wp-admin/admin-functions.php b/wp-admin/admin-functions.php
index 4526904df..969e87e54 100644
--- a/wp-admin/admin-functions.php
+++ b/wp-admin/admin-functions.php
@@ -675,4 +675,26 @@ function get_current_theme() {
 	return $current_theme;
 }
 
+function validate_current_theme() {
+	$theme_loc = 'wp-content/themes';
+	$theme_root = ABSPATH . $theme_loc;
+
+	$template = get_settings('template');
+	$stylesheet = get_settings('stylesheet');
+
+	if (($template != 'default') && (! file_exists("$theme_root/$template/index.php"))) {
+		update_option('template', 'default');
+		update_option('stylesheet', 'default');
+		return false;
+	}
+
+	if (($stylesheet != 'default') && (! file_exists("$theme_root/$stylesheet/style.css"))) {
+		update_option('template', 'default');
+		update_option('stylesheet', 'default');
+		return false;
+	}
+
+	return true;
+}
+
 ?>
\ No newline at end of file
diff --git a/wp-admin/themes.php b/wp-admin/themes.php
index 667aec7d1..b4b61a88e 100644
--- a/wp-admin/themes.php
+++ b/wp-admin/themes.php
@@ -28,7 +28,9 @@ if ($user_level < 9)
 	die (__('Sorry, you must be at least a level 9 user to modify themes.'));
 ?>
 
-<?php if ( isset($activated) ) : ?>
+<?php if ( ! validate_current_theme() ) : ?>
+<div class="updated"><p><?php _e('The active theme is broken.  Reverting to the default theme.'); ?></p></div>
+<?php elseif ( isset($activated) ) : ?>
 <div class="updated"><p><?php _e('New theme activated'); ?></p></div>
 <?php endif; ?>