diff --git a/reference/var/functions/import-request-variables.xml b/reference/var/functions/import-request-variables.xml
index 7bcfe045ae..5eaf5c9076 100644
--- a/reference/var/functions/import-request-variables.xml
+++ b/reference/var/functions/import-request-variables.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.2 $ -->
+<!-- $Revision: 1.3 $ -->
 <!-- splitted from ./en/functions/var.xml, last change in rev 1.34 -->
   <refentry id="function.import-request-variables">
    <refnamediv>
@@ -30,6 +30,13 @@
      variables will overwrite GET variables with the same
      name. Any other other letters then GPC are discarded.
     </simpara>
+    <simpara>
+     The <parameter>prefix</parameter> parameter is used as a variable
+     name prefix, prepended before all variable's name imported into the
+     global scope. So if you have a GET value named "userid", and provide
+     a prefix "pref", then you'll get a global variable named
+     $pref_userid.
+    </simpara>
     <note>
      <para>
       Although the <parameter>prefix</parameter> argument is