diff --git a/homeassistant/components/sensor/imap_email_content.py b/homeassistant/components/sensor/imap_email_content.py
index 225ad08f7d1..714a6c38781 100644
--- a/homeassistant/components/sensor/imap_email_content.py
+++ b/homeassistant/components/sensor/imap_email_content.py
@@ -35,6 +35,7 @@ PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
     vol.Required(CONF_USERNAME): cv.string,
     vol.Required(CONF_PASSWORD): cv.string,
     vol.Required(CONF_SERVER): cv.string,
+    vol.Required(CONF_SENDERS): [cv.string],
     vol.Optional(CONF_PORT, default=DEFAULT_PORT): cv.port,
     vol.Optional(CONF_VALUE_TEMPLATE): cv.template,
     vol.Optional(CONF_FOLDER, default='INBOX'): cv.string,