diff --git a/po/ru.po b/po/ru.po
index 508d28ab9..1f981d0ba 100644
--- a/po/ru.po
+++ b/po/ru.po
@@ -1275,7 +1275,7 @@ msgstr "Ноябрь"
 
 #: js/messages.php:140
 msgid "December"
-msgstr ""
+msgstr "Декабрь"
 
 #. l10n: Short month name
 #: js/messages.php:144 libraries/common.lib.php:1538