diff --git a/homeassistant/components/alexa/smart_home.py b/homeassistant/components/alexa/smart_home.py
index f88d81ab851..df477a3b653 100644
--- a/homeassistant/components/alexa/smart_home.py
+++ b/homeassistant/components/alexa/smart_home.py
@@ -5,15 +5,16 @@ from datetime import datetime
 from uuid import uuid4
 
 from homeassistant.components import (
-    alert, automation, cover, climate, fan, group, input_boolean, light, lock,
-    media_player, scene, script, switch, http, sensor)
+    alert, automation, binary_sensor, cover, climate, fan, group,
+    input_boolean, light, lock, media_player, scene, script, switch, http,
+    sensor)
 import homeassistant.core as ha
 import homeassistant.util.color as color_util
 from homeassistant.util.temperature import convert as convert_temperature
 from homeassistant.util.decorator import Registry
 from homeassistant.const import (
-    ATTR_ENTITY_ID, ATTR_SUPPORTED_FEATURES, ATTR_TEMPERATURE,
-    ATTR_UNIT_OF_MEASUREMENT, CONF_NAME, SERVICE_LOCK,
+    ATTR_DEVICE_CLASS, ATTR_ENTITY_ID, ATTR_SUPPORTED_FEATURES,
+    ATTR_TEMPERATURE, ATTR_UNIT_OF_MEASUREMENT, CONF_NAME, SERVICE_LOCK,
     SERVICE_MEDIA_NEXT_TRACK, SERVICE_MEDIA_PAUSE, SERVICE_MEDIA_PLAY,
     SERVICE_MEDIA_PREVIOUS_TRACK, SERVICE_MEDIA_STOP,
     SERVICE_SET_COVER_POSITION, SERVICE_TURN_OFF, SERVICE_TURN_ON,
@@ -71,6 +72,9 @@ class _DisplayCategory:
     # Indicates media devices with video or photo capabilities.
     CAMERA = "CAMERA"
 
+    # Indicates an endpoint that detects and reports contact.
+    CONTACT_SENSOR = "CONTACT_SENSOR"
+
     # Indicates a door.
     DOOR = "DOOR"
 
@@ -414,6 +418,29 @@ class _AlexaTemperatureSensor(_AlexaInterface):
         }
 
 
+class _AlexaContactSensor(_AlexaInterface):
+    def __init__(self, hass, entity):
+        _AlexaInterface.__init__(self, entity)
+        self.hass = hass
+
+    def name(self):
+        return 'Alexa.ContactSensor'
+
+    def properties_supported(self):
+        return [{'name': 'detectionState'}]
+
+    def properties_retrievable(self):
+        return True
+
+    def get_property(self, name):
+        if name != 'detectionState':
+            raise _UnsupportedProperty(name)
+
+        if self.entity.state == STATE_ON:
+            return 'DETECTED'
+        return 'NOT_DETECTED'
+
+
 class _AlexaThermostatController(_AlexaInterface):
     def __init__(self, hass, entity):
         _AlexaInterface.__init__(self, entity)
@@ -625,6 +652,32 @@ class _SensorCapabilities(_AlexaEntity):
             yield _AlexaTemperatureSensor(self.hass, self.entity)
 
 
+@ENTITY_ADAPTERS.register(binary_sensor.DOMAIN)
+class _BinarySensorCapabilities(_AlexaEntity):
+    TYPE_CONTACT = 'contact'
+
+    def default_display_categories(self):
+        sensor_type = self.get_type()
+        if sensor_type is self.TYPE_CONTACT:
+            return [_DisplayCategory.CONTACT_SENSOR]
+
+    def interfaces(self):
+        sensor_type = self.get_type()
+        if sensor_type is self.TYPE_CONTACT:
+            yield _AlexaContactSensor(self.hass, self.entity)
+
+    def get_type(self):
+        """Return the type of binary sensor."""
+        attrs = self.entity.attributes
+        if attrs.get(ATTR_DEVICE_CLASS) in (
+                'door',
+                'garage_door',
+                'opening',
+                'window',
+        ):
+            return self.TYPE_CONTACT
+
+
 class _Cause:
     """Possible causes for property changes.
 
diff --git a/tests/components/alexa/test_smart_home.py b/tests/components/alexa/test_smart_home.py
index 88c69194407..9596f341447 100644
--- a/tests/components/alexa/test_smart_home.py
+++ b/tests/components/alexa/test_smart_home.py
@@ -694,6 +694,37 @@ def test_temp_sensor(hass):
                             {'value': 42.0, 'scale': 'FAHRENHEIT'})
 
 
+@asyncio.coroutine
+def test_contact_sensor(hass):
+    """Test contact sensor discovery."""
+    device = (
+        'binary_sensor.test_contact',
+        'on',
+        {
+            'friendly_name': "Test Contact Sensor",
+            'device_class': 'door',
+        }
+    )
+    appliance = yield from discovery_test(device, hass)
+
+    assert appliance['endpointId'] == 'binary_sensor#test_contact'
+    assert appliance['displayCategories'][0] == 'CONTACT_SENSOR'
+    assert appliance['friendlyName'] == 'Test Contact Sensor'
+
+    (capability,) = assert_endpoint_capabilities(
+        appliance,
+        'Alexa.ContactSensor')
+    assert capability['interface'] == 'Alexa.ContactSensor'
+    properties = capability['properties']
+    assert properties['retrievable'] is True
+    assert {'name': 'detectionState'} in properties['supported']
+
+    properties = yield from reported_properties(hass,
+                                                'binary_sensor#test_contact')
+    properties.assert_equal('Alexa.ContactSensor', 'detectionState',
+                            'DETECTED')
+
+
 @asyncio.coroutine
 def test_unknown_sensor(hass):
     """Test sensors of unknown quantities are not discovered."""