diff --git a/markdown/extensions/tables.py b/markdown/extensions/tables.py
index cbf711ae5..74f790527 100644
--- a/markdown/extensions/tables.py
+++ b/markdown/extensions/tables.py
@@ -54,6 +54,8 @@ def run(self, parent, blocks):
                 align.append(None)
         # Build table
         table = etree.SubElement(parent, 'table')
+        if border:
+            table.set('border', '1')
         thead = etree.SubElement(table, 'thead')
         self._build_row(header, thead, align, border)
         tbody = etree.SubElement(table, 'tbody')