diff --git a/app/scodoc/gen_tables.py b/app/scodoc/gen_tables.py
index 223fedda..88beeb76 100644
--- a/app/scodoc/gen_tables.py
+++ b/app/scodoc/gen_tables.py
@@ -573,7 +573,7 @@ class GenTable(object):
         """
         doc = ElementTree.Element(
             self.xml_outer_tag,
-            id=self.table_id,
+            id=str(self.table_id),
             origin=self.origin or "",
             caption=self.caption or "",
         )
@@ -587,7 +587,7 @@ class GenTable(object):
                 v = row.get(cid, "")
                 if v is None:
                     v = ""
-                x_cell = ElementTree.Element(cid, value=str(v))
+                x_cell = ElementTree.Element(str(cid), value=str(v))
                 x_row.append(x_cell)
         return sco_xml.XML_HEADER + ElementTree.tostring(doc).decode(scu.SCO_ENCODING)