diff --git a/changelog.d/9911.doc b/changelog.d/9911.doc
new file mode 100644
index 000000000..f7fd9f1ba
--- /dev/null
+++ b/changelog.d/9911.doc
@@ -0,0 +1 @@
+Add `port` argument to the Postgres database sample config section.
\ No newline at end of file
diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml
index e0350279a..d013725cd 100644
--- a/docs/sample_config.yaml
+++ b/docs/sample_config.yaml
@@ -810,6 +810,7 @@ caches:
 #    password: secretpassword
 #    database: synapse
 #    host: localhost
+#    port: 5432
 #    cp_min: 5
 #    cp_max: 10
 #
diff --git a/synapse/config/database.py b/synapse/config/database.py
index 79a02706b..c76ef1e1d 100644
--- a/synapse/config/database.py
+++ b/synapse/config/database.py
@@ -58,6 +58,7 @@ DEFAULT_CONFIG = """\
 #    password: secretpassword
 #    database: synapse
 #    host: localhost
+#    port: 5432
 #    cp_min: 5
 #    cp_max: 10
 #