diff --git a/ldap_user/LdapUserConf.class.php b/ldap_user/LdapUserConf.class.php
index 738f8b0..40c18a2 100644
--- a/ldap_user/LdapUserConf.class.php
+++ b/ldap_user/LdapUserConf.class.php
@@ -657,6 +657,8 @@ class LdapUserConf {
         }
         $value = NULL;
         if (!empty($field_detail['ldap_attr'])) {
+          // Ensure we have a lower case attribute name.
+          $field_detail['ldap_attr'] = drupal_strtolower($field_detail['ldap_attr']);
           if (!ldap_servers_token_is_token($field_detail['ldap_attr'])) {
             $value = $field_detail['ldap_attr']; // literal value
           }