diff --git a/flit/inifile.py b/flit/inifile.py

index 31d016f..8aa434c 100644

--- a/flit/inifile.py

+++ b/flit/inifile.py

@@ -140,8 +140,8 @@ def _validate_config(cp, path):

     if 'description-file' in md_sect:

         description_file = path.parent / md_sect.get('description-file')

-        with description_file.open() as f:

-            raw_desc =  f.read()

+        with description_file.open('r', encoding='utf-8') as f:

+            raw_desc = f.read()

         if description_file.suffix == '.md':

             try:

                 import pypandoc