diff --git a/magic_spoiler/__main__.py b/magic_spoiler/__main__.py
index ff32a358..b2c5882f 100644
--- a/magic_spoiler/__main__.py
+++ b/magic_spoiler/__main__.py
@@ -208,7 +208,8 @@ def open_header(card_xml_file: IO[Any]) -> None:
     :param card_xml_file: Card file path
     """
     card_xml_file.write(
-        "<cockatrice_carddatabase version='3'>\n"
+        "<?xml version='1.0' encoding='UTF-8'?>\n"
+        + "<cockatrice_carddatabase version='3'>\n"
         + "  <!--\n"
         + "  Created At: "
         + datetime.datetime.utcnow().strftime("%a, %b %d %Y, %H:%M:%S")