diff --git a/src/Symfony/Bundle/SecurityBundle/Resources/config/security.xml b/src/Symfony/Bundle/SecurityBundle/Resources/config/security.xml
index d7a4402154523..c5f0408d9985f 100644
--- a/src/Symfony/Bundle/SecurityBundle/Resources/config/security.xml
+++ b/src/Symfony/Bundle/SecurityBundle/Resources/config/security.xml
@@ -164,7 +164,9 @@
 
         <!-- Provisioning -->
         <service id="security.user.provider.in_memory" class="Symfony\Component\Security\Core\User\InMemoryUserProvider" abstract="true" />
-        <service id="security.user.provider.in_memory.user" class="Symfony\Component\Security\Core\User\User" abstract="true" />
+        <service id="security.user.provider.in_memory.user" class="Symfony\Component\Security\Core\User\User" abstract="true">
+            <deprecated>The "%service_id%" service is deprecated since Symfony 4.1 and will be removed in 5.0.</deprecated>
+        </service>
 
         <service id="security.user.provider.ldap" class="Symfony\Component\Security\Core\User\LdapUserProvider" abstract="true">
             <argument /> <!-- security.ldap.ldap -->