diff --git a/ftoverride.php b/ftoverride.php
index bc908a8..ccceef9 100644
--- a/ftoverride.php
+++ b/ftoverride.php
@@ -316,6 +316,22 @@ function ftoverride_civicrm_pre($op, $objectName, $id, &$params) {
   }
 }
 
+/**
+ * Implements hook_civicrm_validateForm().
+ *
+ * @link http://wiki.civicrm.org/confluence/display/CRMDOC/hook_civicrm_validateForm
+ */
+function ftoverride_civicrm_validateForm($formName, &$fields, &$files, &$form, &$errors) {
+  if ('CRM_Contribute_Form_Contribution_Main' == $formName) {
+    if (!empty($fields['designation'])
+      && $fields['designation'] == 'other_financial_type'
+      && empty($fields['designation_note'])
+    ) {
+      $errors['designation_note'] = ts('Please provide other information about designation.');
+    }
+  }
+}
+
 /**
  * Implements hook_civicrm_buildAmount().
  *