diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 0b0e10d0..a95c77f8 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -15,6 +15,7 @@ Added
 * Added optional hack to use Bluetooth address instead of UUID on macOS.
 * Added ``BleakScanner.find_device_by_name()`` class method.
 * Added optional command line argument to use debug log level to all applicable examples.
+* Make sure the disconnect monitor task is properly cancelled on the BlueZ client.
 
 Changed
 -------
diff --git a/bleak/backends/bluezdbus/client.py b/bleak/backends/bluezdbus/client.py
index 8bf88ff0..da2f9f7a 100644
--- a/bleak/backends/bluezdbus/client.py
+++ b/bleak/backends/bluezdbus/client.py
@@ -161,6 +161,8 @@ def on_value_changed(char_path: str, value: bytes) -> None:
         )
         self._remove_device_watcher = lambda: manager.remove_device_watcher(watcher)
 
+        local_disconnect_monitor_event = asyncio.Event()
+
         try:
             try:
                 #
@@ -197,10 +199,10 @@ def on_value_changed(char_path: str, value: bytes) -> None:
                 self._is_connected = True
 
                 # Create a task that runs until the device is disconnected.
-                self._disconnect_monitor_event = asyncio.Event()
+                self._disconnect_monitor_event = local_disconnect_monitor_event
                 asyncio.ensure_future(
                     self._disconnect_monitor(
-                        self._bus, self._device_path, self._disconnect_monitor_event
+                        self._bus, self._device_path, local_disconnect_monitor_event
                     )
                 )
 
@@ -246,6 +248,9 @@ def on_value_changed(char_path: str, value: bytes) -> None:
 
                 raise
         except BaseException:
+            # this effectively cancels the disconnect monitor in case the event
+            # was not triggered by a D-Bus callback
+            local_disconnect_monitor_event.set()
             self._cleanup_all()
             raise