diff --git a/esphome/components/i2c.py b/esphome/components/i2c.py
index 0ee857f47b..eaeb4b2a37 100644
--- a/esphome/components/i2c.py
+++ b/esphome/components/i2c.py
@@ -16,7 +16,7 @@ CONFIG_SCHEMA = cv.Schema({
     vol.Optional(CONF_SDA, default='SDA'): pins.input_pin,
     vol.Optional(CONF_SCL, default='SCL'): pins.input_pin,
     vol.Optional(CONF_FREQUENCY): vol.All(cv.frequency, vol.Range(min=0, min_included=False)),
-    vol.Optional(CONF_SCAN): cv.boolean,
+    vol.Optional(CONF_SCAN, default=True): cv.boolean,
 
     vol.Optional(CONF_RECEIVE_TIMEOUT): cv.invalid("The receive_timeout option has been removed "
                                                    "because timeouts are already handled by the "