diff --git a/homeassistant/components/mqtt/discovery.py b/homeassistant/components/mqtt/discovery.py
index 688912070bd..885c14f609f 100644
--- a/homeassistant/components/mqtt/discovery.py
+++ b/homeassistant/components/mqtt/discovery.py
@@ -235,8 +235,8 @@ async def async_start(hass: HomeAssistantType, discovery_topic, hass_config,
                 key = DEVICE_ABBREVIATIONS.get(key, key)
                 device[key] = device.pop(abbreviated_key)
 
-        base = payload.pop(TOPIC_BASE, None)
-        if base:
+        if TOPIC_BASE in payload:
+            base = payload.pop(TOPIC_BASE)
             for key, value in payload.items():
                 if isinstance(value, str) and value:
                     if value[0] == TOPIC_BASE and key.endswith('_topic'):