diff --git a/CHANGES.txt b/CHANGES.txt
index c7f32ea4..f90eae6f 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -4,6 +4,14 @@ Unreleased
 Bugfix
 ~~~~~~
 
+- ``BaseWSGIServer.close()`` now shuts down the task dispatcher's worker
+  threads, matching ``MultiSocketServer.close()``'s existing behavior. This
+  matters most for the common single-listen-address case, where
+  ``create_server()`` returns a bare ``BaseWSGIServer`` (not wrapped in
+  ``MultiSocketServer``), so calling ``.close()`` directly used to leave the
+  dispatcher's worker threads running. See
+  https://github.com/Pylons/waitress/issues/480
+
 - Renamed the HTTP header "Trailers" to "Trailer" to fix a typo and comply with
   the correct header name as specified in RFC 7230.
 
diff --git a/src/waitress/server.py b/src/waitress/server.py
index c56530a0..73b40a10 100644
--- a/src/waitress/server.py
+++ b/src/waitress/server.py
@@ -355,6 +355,15 @@ def print_listen(self, format_str):  # pragma: no cover
 
     def close(self):
         self.trigger.close()
+        # Ensure the task dispatcher's worker threads are stopped too,
+        # matching MultiSocketServer.close()'s existing behavior. This
+        # matters most for the common single-listen-address case,
+        # where create_server() returns a bare BaseWSGIServer (not
+        # wrapped in MultiSocketServer), so calling .close() on it is
+        # the only place a caller has to shut things down -- without
+        # this, the dispatcher's worker threads were left running
+        # after close(). See GH #480.
+        self.task_dispatcher.shutdown()
         return wasyncore.dispatcher.close(self)
 
 
diff --git a/tests/test_server.py b/tests/test_server.py
index cede49a7..da3c8d0b 100644
--- a/tests/test_server.py
+++ b/tests/test_server.py
@@ -124,6 +124,25 @@ def test_run(self):
         inst.run()
         self.assertTrue(inst.task_dispatcher.was_shutdown)
 
+    def test_close_shuts_down_task_dispatcher(self):
+        """
+        Regression test for
+        https://github.com/Pylons/waitress/issues/480
+
+        close() must shut down the task dispatcher's worker threads
+        directly, not only as a side effect of run()'s
+        SystemExit/KeyboardInterrupt handling. This matters most for
+        the common single-listen-address case, where create_server()
+        returns a bare BaseWSGIServer (not wrapped in
+        MultiSocketServer), so calling .close() directly -- without
+        ever calling .run() -- is the only place a caller has to shut
+        things down.
+        """
+        inst = self._makeOneWithMap(_start=False)
+        inst.task_dispatcher = DummyTaskDispatcher()
+        inst.close()
+        self.assertTrue(inst.task_dispatcher.was_shutdown)
+
     def test_run_base_server(self):
         inst = self._makeOneWithMulti(_start=False)
         inst.asyncore = DummyAsyncore()