diff --git a/mdx/_rules/check_reqattr.xsl b/mdx/_rules/check_reqattr.xsl
index 3bdb565d..9052ff01 100644
--- a/mdx/_rules/check_reqattr.xsl
+++ b/mdx/_rules/check_reqattr.xsl
@@ -33,6 +33,8 @@
         Currently only a single attribute, documented at:
         https://www.eduroam.cz/attributes/eduroamUID
 
+    * SAML V2.0 Subject Identifier Attributes Profile
+        https://docs.oasis-open.org/security/saml-subject-id-attr/v1.0/cs01/saml-subject-id-attr-v1.0-cs01.pdf
 
     Author: Ian A. Young <ian@iay.org.uk>
 
@@ -493,6 +495,16 @@
                 <!-- OK -->
             </xsl:when>
 
+            <!--
+                SAML V2.0 Subject Identifier Attributes Profile Version 1.0
+            -->
+            <xsl:when test="
+                @Name = 'urn:oasis:names:tc:SAML:attribute:subject-id' or
+                @Name = 'urn:oasis:names:tc:SAML:attribute:pairwise-id'
+                ">
+                <!-- OK -->
+            </xsl:when>
+
             <!--
                 Otherwise unknown attribute names.
             -->