diff --git a/homeassistant/components/ping/device_tracker.py b/homeassistant/components/ping/device_tracker.py
index c4d88f6061c..c0effda7a55 100644
--- a/homeassistant/components/ping/device_tracker.py
+++ b/homeassistant/components/ping/device_tracker.py
@@ -21,7 +21,7 @@ CONF_PING_COUNT = "count"
 
 PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend(
     {
-        vol.Required(const.CONF_HOSTS): {cv.string: cv.string},
+        vol.Required(const.CONF_HOSTS): {cv.slug: cv.string},
         vol.Optional(CONF_PING_COUNT, default=1): cv.positive_int,
     }
 )