diff --git a/user/externallib.php b/user/externallib.php
index f03b9b858a9..803fce52414 100644
--- a/user/externallib.php
+++ b/user/externallib.php
@@ -180,7 +180,8 @@ class core_user_external extends external_api {
             // Make sure we validate current user info as handled by current GUI. See user/editadvanced_form.php func validation().
             if (!validate_email($user['email'])) {
                 throw new invalid_parameter_exception('Email address is invalid: '.$user['email']);
-            } else if ($DB->record_exists('user', array('email' => $user['email'], 'mnethostid' => $user['mnethostid']))) {
+            } else if (empty($CFG->allowaccountssameemail) &&
+                    $DB->record_exists('user', array('email' => $user['email'], 'mnethostid' => $user['mnethostid']))) {
                 throw new invalid_parameter_exception('Email address already exists: '.$user['email']);
             }
             // End of user info validation.