diff --git a/manifests/db.pp b/manifests/db.pp
index f4fb48c..5f0a633 100644
--- a/manifests/db.pp
+++ b/manifests/db.pp
@@ -151,6 +151,9 @@ define oslo::db (
         }
       }
       Oslo::Dbconn::Postgres: {
+        warning("Support for PostgreSQL has been deprecated and will be \
+removed in a future release")
+
         $backend_package = undef
         require 'postgresql::lib::python'
       }
diff --git a/releasenotes/notes/deprecate-postgresql-d839e8192ee3418b.yaml b/releasenotes/notes/deprecate-postgresql-d839e8192ee3418b.yaml
new file mode 100644
index 0000000..435239f
--- /dev/null
+++ b/releasenotes/notes/deprecate-postgresql-d839e8192ee3418b.yaml
@@ -0,0 +1,5 @@
+---
+deprecations:
+  - |
+    Support for PostgreSQL has been deprecated and will be removed in a future
+    release.