diff --git a/ironic/api/controllers/v1/node.py b/ironic/api/controllers/v1/node.py
index 47883740d6..e911e6df7a 100644
--- a/ironic/api/controllers/v1/node.py
+++ b/ironic/api/controllers/v1/node.py
@@ -466,10 +466,7 @@ class NodesController(rest.RestController):
 
     @wsme_pecan.wsexpose(None, unicode, status_code=204)
     def delete(self, node_id):
-        """Delete a node.
-
-        TODO(deva): don't allow deletion of an associated node.
-        """
+        """Delete a node."""
         if self._from_chassis:
             raise exception.OperationNotPermitted
 
diff --git a/ironic/common/exception.py b/ironic/common/exception.py
index 1c3db8955c..cbfa9a8fb4 100644
--- a/ironic/common/exception.py
+++ b/ironic/common/exception.py
@@ -274,6 +274,10 @@ class NodeLocked(InvalidState):
     message = _("Node %(node)s is locked by another process.")
 
 
+class NodeAssociated(InvalidState):
+    message = _("Node %(node)s is associated with instance %(instance)s.")
+
+
 class PortNotFound(NotFound):
     message = _("Port %(port)s could not be found.")
 
diff --git a/ironic/db/sqlalchemy/api.py b/ironic/db/sqlalchemy/api.py
index f361dae4eb..df89705baf 100644
--- a/ironic/db/sqlalchemy/api.py
+++ b/ironic/db/sqlalchemy/api.py
@@ -303,6 +303,9 @@ class Connection(api.Connection):
                 raise exception.NodeNotFound(node=node)
             if node_ref['reservation'] is not None:
                 raise exception.NodeLocked(node=node)
+            if node_ref['instance_uuid'] is not None:
+                raise exception.NodeAssociated(node=node,
+                                            instance=node_ref['instance_uuid'])
 
             # Get node ID, if an UUID was supplied. The ID is
             # required for deleting all ports, attached to the node.
diff --git a/ironic/tests/api/test_nodes.py b/ironic/tests/api/test_nodes.py
index 334126e6a0..b0fdf75feb 100644
--- a/ironic/tests/api/test_nodes.py
+++ b/ironic/tests/api/test_nodes.py
@@ -370,6 +370,12 @@ class TestDelete(base.FunctionalTest):
                                expect_errors=True)
         self.assertEqual(response.status_int, 403)
 
+    def test_delete_associated(self):
+        ndict = dbutils.get_test_node(instance_uuid='fake-uuid-1234')
+        self.post_json('/nodes', ndict)
+        response = self.delete('/nodes/%s' % ndict['uuid'], expect_errors=True)
+        self.assertEqual(response.status_int, 409)
+
 
 class TestPut(base.FunctionalTest):
 
diff --git a/ironic/tests/db/test_nodes.py b/ironic/tests/db/test_nodes.py
index 25edfe7e63..206b3a2190 100644
--- a/ironic/tests/db/test_nodes.py
+++ b/ironic/tests/db/test_nodes.py
@@ -155,6 +155,11 @@ class DbNodeTestCase(base.DbTestCase):
         self.assertRaises(exception.NodeLocked,
                           self.dbapi.destroy_node, n['id'])
 
+    def test_destroy_associated_node(self):
+        n = self._create_test_node(instance_uuid='fake-uuid-1234')
+        self.assertRaises(exception.NodeAssociated,
+                          self.dbapi.destroy_node, n['uuid'])
+
     def test_ports_get_destroyed_after_destroying_a_node(self):
         n = self._create_test_node()
         node_id = n['id']