diff --git a/CRM/Contact/BAO/Contact.php b/CRM/Contact/BAO/Contact.php
index 2599d975f4cd..d20e155462aa 100644
--- a/CRM/Contact/BAO/Contact.php
+++ b/CRM/Contact/BAO/Contact.php
@@ -179,6 +179,12 @@ public static function add(&$params) {
         $contact->display_name = $contact->sort_name = CRM_Utils_Array::value('organization_name', $params, '');
       }
     }
+    if (strlen($contact->display_name) > 128) {
+      $contact->display_name = substr($contact->display_name, 0,128);
+    }
+    if (strlen($contact->sort_name) > 128) {
+      $contact->sort_name = substr($contact->sort_name, 0,128);
+    }
 
     $privacy = CRM_Utils_Array::value('privacy', $params);
     if ($privacy &&
diff --git a/tests/phpunit/api/v3/ContactTest.php b/tests/phpunit/api/v3/ContactTest.php
index fb7e01a23755..c2f4f94e21e7 100644
--- a/tests/phpunit/api/v3/ContactTest.php
+++ b/tests/phpunit/api/v3/ContactTest.php
@@ -2360,6 +2360,21 @@ public function testContactCreateFormatIsSuccessFalse() {
     $this->assertEquals(0, $result);
   }
 
+  /**
+   * Test long display names.
+   *
+   * CRM-21258
+   */
+  public function testContactCreateLongDisplayName() {
+    $result = $this->callAPISuccess('Contact', 'Create', array(
+      'first_name' => str_pad('a', 64, 'a'),
+      'last_name' => str_pad('a', 64, 'a'),
+      'contact_type' => 'Individual',
+    ));
+    $this->assertEquals('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa', $result['values'][$result['id']]['display_name']);
+    $this->assertEquals('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa, aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa', $result['values'][$result['id']]['sort_name']);
+  }
+
   /**
    * Test Single Entity format.
    */