diff --git a/catalog.c b/catalog.c
index 89a2c266..006b4aa1 100644
--- a/catalog.c
+++ b/catalog.c
@@ -3461,6 +3461,8 @@ xmlCatalogSetDefaults(xmlCatalogAllow allow) {
  * xmlCatalogSetDefaultPrefer:
  * @prefer:  the default preference for delegation
  *
+ * DEPRECATED: This setting is global and not thread-safe.
+ *
  * Allows to set the preference between public and system for deletion
  * in XML Catalog resolution. C.f. section 4.1.1 of the spec
  * Values accepted are XML_CATA_PREFER_PUBLIC or XML_CATA_PREFER_SYSTEM
diff --git a/include/libxml/catalog.h b/include/libxml/catalog.h
index 02fa7ab2..442092a4 100644
--- a/include/libxml/catalog.h
+++ b/include/libxml/catalog.h
@@ -161,6 +161,7 @@ XMLPUBFUN xmlChar *
  */
 XMLPUBFUN int
 		xmlCatalogSetDebug	(int level);
+XML_DEPRECATED
 XMLPUBFUN xmlCatalogPrefer
 		xmlCatalogSetDefaultPrefer(xmlCatalogPrefer prefer);
 XMLPUBFUN void