diff --git a/usr.bin/calendar/calendars/calendar.birthday b/usr.bin/calendar/calendars/calendar.birthday
index c819064bb7b..9cc9e21d23e 100644
--- a/usr.bin/calendar/calendars/calendar.birthday
+++ b/usr.bin/calendar/calendars/calendar.birthday
@@ -197,6 +197,7 @@
 09/08	King Richard I of England born, 1157
 09/08	Peter Sellers born in Southsea, England, 1925
 09/09	Chinese Communist Party Chairman Mao Tse-Tung dies at age 82, 1976
+09/09	Dennis Ritchie born, 1941
 09/12	Jesse Owens born, 1913
 09/13	Walter Reed born, 1851
 09/15	Agatha Christie born in Torquay, England, 1890