diff --git a/mirrormanager2/views.py b/mirrormanager2/views.py
index 630d72e7..626b0cdc 100644
--- a/mirrormanager2/views.py
+++ b/mirrormanager2/views.py
@@ -960,6 +960,10 @@ def host_category_url_new(host_id, hc_id):
             url = url[:-1]
         host_category_u.url = url
 
+        if url in [url.url for url in hcobj.urls]:
+            flask.flash(f"URL Not Added: {url} already exists on {hcobj.category.name}", "error")
+            return flask.redirect(flask.url_for("base.host_view", host_id=host_id))
+
         # If the user is *not* an admin, keep the current private flag
         if not is_mirrormanager_admin(flask.g.fas_user):
             host_category_u.private = private
diff --git a/tests/test_ui_app.py b/tests/test_ui_app.py
index 61f7e6af..c2259fd3 100644
--- a/tests/test_ui_app.py
+++ b/tests/test_ui_app.py
@@ -1101,7 +1101,7 @@ def test_host_category_url_new_auth(client, user):
     output = client.post("/host/2/category/3/url/new", data=post_data, follow_redirects=True)
     assert output.status_code == 200
     data = output.get_data(as_text=True)
-    assert "Could not add Category URL to the host" in data
+    assert "URL Not Added: http://pingoured.fr/pub/Fedora already exists on Fedora Linux" in data
     assert '<h2 class="mb-0"><span class="fa fa-server"></span>' in data
     assert "<title>Host - MirrorManager</title>" in data
     assert 'action="/host/2/category/3/url/9/delete">' in data