diff --git a/homeassistant/components/alert/__init__.py b/homeassistant/components/alert/__init__.py
index 69edb3ee001..73be34e6d33 100644
--- a/homeassistant/components/alert/__init__.py
+++ b/homeassistant/components/alert/__init__.py
@@ -48,7 +48,12 @@ ALERT_SCHEMA = vol.Schema(
         vol.Required(CONF_NAME): cv.string,
         vol.Required(CONF_ENTITY_ID): cv.entity_id,
         vol.Required(CONF_STATE, default=STATE_ON): cv.string,
-        vol.Required(CONF_REPEAT): vol.All(cv.ensure_list, [vol.Coerce(float)]),
+        vol.Required(CONF_REPEAT): vol.All(
+            cv.ensure_list,
+            [vol.Coerce(float)],
+            # Minimum delay is 1 second = 0.016 minutes
+            [vol.Range(min=0.016)],
+        ),
         vol.Required(CONF_CAN_ACK, default=DEFAULT_CAN_ACK): cv.boolean,
         vol.Required(CONF_SKIP_FIRST, default=DEFAULT_SKIP_FIRST): cv.boolean,
         vol.Optional(CONF_ALERT_MESSAGE): cv.template,