diff --git a/src/web/pages_admin.ml b/src/web/pages_admin.ml
index 1fbb1287c3ff15ecf0ba0ba6c314a353e9776121..8e4f10f7c7287502896bac0e3d8a6994e7541b37 100644
--- a/src/web/pages_admin.ml
+++ b/src/web/pages_admin.ml
@@ -1306,6 +1306,10 @@ let election_draft_voters uuid se maxvoters () =
             b [txt (s_ "Warning:")];
             txt " ";
             txt (s_ "you have to make sure that these email addresses are valid. You won't be able to change the email addresses once the election is set up. Voters with invalid email addresses won't be able to vote.");
+            br ();
+            b [txt (s_ "Warning:")];
+            txt " ";
+            txt (s_ "Duplicate identities are not allowed and are automatically merged. If two voters have the same email address, use different logins.");
           ];
         form;
         div [