diff --git a/includes/bootstrap.inc b/includes/bootstrap.inc
index d9ad856..93c98b5 100644
--- a/includes/bootstrap.inc
+++ b/includes/bootstrap.inc
@@ -927,6 +927,28 @@ function variable_initialize($conf = array()) {
 }
 
 /**
+ * Checks if a persistant variable exists.
+ *
+ * The persistance check is done relative to the page load (or last time the
+ * $conf variable was reloaded).
+ *
+ * @param string $name
+ *   The name of the variable to return.
+ *
+ * @return boolean
+ *   True or false if the variable currently exists.
+ *
+ * @see variable_del()
+ * @see variable_set()
+ * @see variable_get()
+ */
+function variable_exists($name) {
+  global $conf;
+
+  return array_key_exists($name, $conf);
+}
+
+/**
  * Returns a persistent variable.
  *
  * Case-sensitivity of the variable_* functions depends on the database