diff --git a/mongodb_field_storage/mongodb_field_storage.install b/mongodb_field_storage/mongodb_field_storage.install
index cf0491f..281d70f 100644
--- a/mongodb_field_storage/mongodb_field_storage.install
+++ b/mongodb_field_storage/mongodb_field_storage.install
@@ -10,3 +10,10 @@
 function mongodb_field_storage_install() {
   variable_set('field_storage_default', 'mongodb_field_storage');
 }
+
+/**
+ * Implements hook_disable().
+ */
+function mongodb_field_storage_disable() {
+  variable_del('field_storage_default');
+}