diff --git a/config_tempest/main.py b/config_tempest/main.py
index d685e6f2..c30ac5ef 100755
--- a/config_tempest/main.py
+++ b/config_tempest/main.py
@@ -83,10 +83,10 @@ def load_basic_defaults(conf):
             ("log_file", "tempest.log")
         ],
         "identity": [
-            ("username", "demo"),
+            ("username", "demo_tempestconf"),
             ("password", "secrete"),
             ("project_name", "demo"),
-            ("alt_username", "alt_demo"),
+            ("alt_username", "alt_demo_tempestconf"),
             ("alt_password", "secrete"),
             ("alt_project_name", "alt_demo"),
             ("disable_ssl_certificate_validation", "true")
diff --git a/releasenotes/notes/unique-demo-user-name-fd9428a2d8efdc82.yaml b/releasenotes/notes/unique-demo-user-name-fd9428a2d8efdc82.yaml
new file mode 100644
index 00000000..4b0f766e
--- /dev/null
+++ b/releasenotes/notes/unique-demo-user-name-fd9428a2d8efdc82.yaml
@@ -0,0 +1,7 @@
+---
+features:
+  - |
+   Tempestconf now creates users with name that ends with '_tempestconf'.
+   This change makes sure that collisions are avoided. For example, if the
+   system already contains a user named 'demo_tempestconf' then it was
+   probably created by tempestconf.