diff --git a/owslib/csw.py b/owslib/csw.py
index <HASH>..<HASH> 100644
--- a/owslib/csw.py
+++ b/owslib/csw.py
@@ -201,6 +201,7 @@ class CatalogueServiceWeb:
         else:
             # construct request
             node0 = etree.Element(util.nspath_eval('csw:GetRecords', namespaces))
+            node0.set('xmlns:ows', namespaces['ows'])
             node0.set('outputSchema', outputschema)
             node0.set('outputFormat', format)
             node0.set('version', self.version)
force ows namespace decl (for validating CSW servers and owslib clients using xml.etree)